IN THE UNITED STATES DISTRICT COURT

FOR THE WESTERN DISTRICT OF TEXAS 

WACO DIVISION

DROPBOX, INC.,

Plaintiff / Counterclaim 

Defendant,

v.

MOTION OFFENSE, LLC, 

Defendant / Counterclaim 

Plaintiff.

Civil Action No. 6:20-cv-00251-ADA

JURY TRIAL DEMANDED 

MOTION OFFENSE, LLC, 

Plaintiff,

v.

DROPBOX, INC.,

Defendant.

 Civil Action No. 6:21-cv-00758-ADA

 JURY TRIAL DEMANDED

MOTION OFFENSE, LLC’S REPY ON ITS

MOTION FOR PARTIAL SUMMARY JUDGMENT AGAINST 

DROPBOX AFFIRMATIVE DEFENSES NOT INVOLVING PRIOR ART [DKT. 198]

Dated: March 31, 2023 Timothy Devlin (DE Bar No. 4241)

Alex Chan (Texas Bar No. 24108051)

Donald Puckett (Texas Bar No. 24013358)

Derek Dahlgren (pro hac vice)

Srikant Cheruvu pro hac vice)

Andrew Sherman (pro hac vice)

DEVLIN LAW FIRM LLC

1526 Gilpin Ave.,

Wilmington, DE 19806

Telephone: (302) 449-9010

ATTORNEYS FOR MOTION OFFENSE, LLC

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 1 of 15
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TABLE OF CONTENTS

SUMMARY OF REPLY................................................................................................................ 1

ARGUMENT AND AUTHORITIES............................................................................................. 2

I. Partial Summary Judgment Is Required Against Dropbox’s Inequitable Conduct 

Affirmative Defense........................................................................................................................ 2

A. Dropbox Significantly Mis-States the Applicable Legal Standards................................. 2

B. Dropbox Has Not Presented Evidence Sufficient to Create a Genuine Dispute of Fact 

Requiring a Trial on Inequitable Conduct .................................................................................. 5

1. Dropbox Has Not Identified a Specific Reference or Any Specific Information that 

the Patent Applicant Allegedly Failed to Disclose ................................................................. 5

2. Dropbox Has Not Presented Any Evidence that the Allegedly Undisclosed 

Information Was Material to Patentability ............................................................................. 6

3. Dropbox Has Not Presented Any Evidence of Motion Offense’s Allegedly Deceitful 

Intent ...................................................................................................................................... 7

II. Partial Summary Judgment is Required Against Dropbox’s Prosecution History Estoppel 

Defense ........................................................................................................................................... 8

III. Partial Summary Judgment is Required Against Dropbox’s Ensnarement Defense ........... 9

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 2 of 15
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TABLE OF AUTHORITIES

Cases

01 Communique Lab., Inc. v. Citrix Sys.

889 F.3d 735 (Fed. Cir. 2018)..................................................................................................... 6

1

st Media, LLC v. Elec. Arts, Inc., 

694 F.3d 1367 (Fed. Cir. 2012)................................................................................................... 3

Argina Tech. Ltd. v. Nissan Motor Co., 

2022 U.S. Dist. LEXIS 23489 (E.D. Tex. Oct. 24, 2022) .......................................................... 9

Cao Lighting, Inc. v. Feit Elc. Co., 

2023 U.S. Dist LEXIS 45494 (C.D. Cal. March 16, 2023) ........................................................ 8

DeCurtis LLC v. Carnival Corp., 

2023 U.S. Dist. LEXIS 26590 (S.D. Fla. Feb. 8, 2023).............................................................. 5

Golden Hour Data Sys. v. emsCharts, Inc., 

2012 U.S. Dist LEXIS 114989 (E.D. Tex. Aug. 15, 2012) ........................................................ 6

In re Method of Processing Ethanol Byproducts, 

2014 U.S. Dist. LEXIS 88512 (S.D. Ind. June 30, 2014)........................................................... 3

Interactive Pictures Corp. v. Infinite Pictures, Inc., 

274 F.3d 1371 (Fed. Cir. 2001)................................................................................................... 9

Jang v. Boston Sci. Corp., 

872 F.3d 1275 (Fed. Cir. 2017)............................................................................................. 9, 10

Meris U.S.A., Inc. v. Faro Techs., Inc., 

882 F.Supp.2d 160 (Dist. Mass. 2011) ....................................................................................... 3

Monkeymedia, Inc. v. Twentieth Century Fox Home Entm’t, LLC, 

242 F.Supp.3d 551 (W.D. Tex. 2017)......................................................................................... 8

Navico Int’l v. Garmin Int’l, 

2017 U.S. Dist. LEXIS 136930 (E.D. Tex. Aug. 7, 2017) ......................................................... 8

ROY-G BIV Corp. v. ABB, Ltd., 

63 F.Supp.3d 690 (E.D. Tex. 2014)............................................................................................ 8

Scanner Techs. Corp. v. ICOS Vision Sys. Corp., 

528 F.3d 1365 (Fed. Cir. 2008)................................................................................................... 4

Therasense, Inc. v. Becton, Dickinson & Co, 

649 F.3d 1276 (Fed. Cir. 2011).......................................................................................... passim

Tinnus Enters., LLC v. Telebrands Corp., 

2017 U.S. Dist. LEXIS 219839 (E.D. Tex. Aug. 15, 2017) ....................................................... 8

Uniloc USA, Inc. v. Microsoft Corp., 

632 F.3d 1292 (Fed. Cir 2011).................................................................................................... 7

Zenith Elecs. Corp v. PDI Comm. Sys., Inc., 

522 F.3d 1348 (Fed. Cir. 2008)................................................................................................... 7

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 3 of 15
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Rules

Fed. R. Civ. P. 56............................................................................................................................ 7

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SUMMARY OF REPLY

Dropbox expressly acknowledges that partial summary judgment is appropriate against 

Dropbox’s Third, Fourth, and Ninth Affirmative Defenses. See Response, Dkt. 235 at 1 n.1. 

Dropbox’s attempt to salvage its Eleventh Affirmative Defense (“Inequitable Conduct”) 

is unavailing. Dropbox literally ignores the effect of the Federal Circuit’s 2011 en banc decision 

in Therasense, Inc. v. Becton, Dickinson & Co, 649 F.3d 1276 (Fed. Cir. 2011), which 

significantly revised the legal standards for inequitable conduct. Dropbox relies entirely on preTherasense cases, essentially urging the Court to decide this motion using pre-Therasense law. 

Using the Therasense legal standards for inequitable conduct, the Court can decide this 

motion easily. Dropbox has not identified any specific prior art reference or other information 

that the patent applicant allegedly failed to disclose to the USPTO. Dropbox has presented no

admissible evidence to show that any undisclosed information was material to patentability, and

Dropbox’s evidence of deceptive intent is glaringly deficient. Dropbox’s Response asserts only 

that the patent applicant and prosecution attorneys “should have known” the technical features of 

Dropbox—clearly demonstrating that Dropbox is attempting to assert a negligence or gross 

negligence theory of inequitable conduct that was expressly rejected in Therasense. 

Partial summary judgment also is required against Dropbox’s Fifth Affirmative Defense 

(“Prosecution History Estoppel”) and Tenth Affirmative Defense (“Ensnarement”). Dropbox’s 

Response brief fails to meet Dropbox’s summary judgment burden because Dropbox does not 

cite even one piece of evidence in favor of either defense; nor does Dropbox even articulate a 

specific theory of either defense. Dropbox cannot be allowed to surprise Motion Offense by 

unveiling its theories and evidence in support of these affirmative defenses for the first time at 

trial. Partial summary judgment is required against both of these defenses.

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ARGUMENT AND AUTHORITIES

I. PARTIAL SUMMARY JUDGMENT IS REQUIRED AGAINST DROPBOX’S 

INEQUITABLE CONDUCT AFFIRMATIVE DEFENSE

A. Dropbox Significantly Mis-States the Applicable Legal Standards

Dropbox cites two cases from 2006 to assert that “[s]ummary judgment on the issue of 

inequitable conduct is uncommon given the ‘inherently factual nature of the issue of intent.’” See 

Response, Dkt. 235 at 2-3. That was an accurate statement of the law in 2006, but it is a wildly 

inaccurate statement of the law today. 

In 2011, the en banc Federal Circuit decided to revisit the legal standards applicable to 

the defense of inequitable conduct “[r]ecognizing the problems created by the expansion and 

overuse1of the inequitable conduct doctrine . . . .” Therasense, Inc. v. Becton, Dickinson & Co, 

649 F.3d 1276, 1285 (Fed. Cir. 2011, en banc). The Therasense court noted that, in the past, the 

Federal Circuit had adopted “low standards” for both the “materiality” and “intent to deceive” 

elements of inequitable conduct. See id. at 1287-88. The Federal Circuit had “embraced these 

reduced standards . . . to foster full disclosure to the PTO,” but the low standards for inequitable 

conduct “had numerous unforeseen and unintended consequences.” Id. at 1288. The Therasense

court found that inequitable conduct had “become a significant litigation strategy” used too 

frequently by accused infringers in litigation to “cast a dark cloud over the patent’s validity and 

paint the patentee as a bad actor.” Id. “Because the doctrine focuses on the moral turpitude of the 

patentee with ruinous consequences for the reputation of his patent attorney, it discourages 

settlement and deflects attention from the merits of validity and infringement issues.” Id.

The Therasense court described inequitable conduct as the “atomic bomb” of patent law. 

See id. at 1288. Therasense noted that “[i]nequitable conduct has been overplayed, is appearing 

1 Throughout this brief, emphasis in quotations has been added unless stated otherwise.

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 6 of 15
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in nearly every patent suit, and is cluttering up the patent system.” Id at 1289. “The habit of 

charging inequitable conduct in almost every major patent case has become an absolute 

plague.” Id. “Left unfettered, the inequitable conduct doctrine has plagued not only the courts 

but also the entire patent system.” Id.

To remedy the serious harms to the patent system that had been caused by lax legal 

standards for inequitable conduct, the en banc Federal Circuit “tighten[ed] the standards for 

finding both intent and materiality in order to redirect a doctrine that has been overused to the 

detriment of the public.” Id. at 1290. The Therasense opinion itself, and subsequent court 

decisions applying Therasense, leave no doubt that Therasense rewrote the legal standards for 

inequitable conduct in ways that radically departed from prior law. See, e.g., 1

st Media, LLC v. 

Elec. Arts, Inc., 694 F.3d 1367, 1372 (Fed. Cir. 2012) (“This court’s recent opinion in 

Therasense changed the standard for proving inequitable conduct based on nondisclosure of a 

reference to the PTO”); Meris U.S.A., Inc. v. Faro Techs., Inc., 882 F.Supp.2d 160, 166 (Dist. 

Mass. 2011) (“Since the issuance of that opinion, the Federal Circuit has caused a sea-change in 

the law of inequitable conduct”); In re Method of Processing Ethanol Byproducts, 2014 U.S. 

Dist. LEXIS 88512 at *31, 2014 WL 2938183 (S.D. Ind. June 30, 2014) (“Therasense makes an 

inequitable conduct claim extraordinarily difficult to prove”). 

Therasense expressly held that the “intent and materiality” elements of inequitable 

conduct “are separate requirements.” Therasense, 649 F.3d at 1290.2 The Therasense court then 

proceeded to tighten the legal standards for both elements of inequitable conduct. 

2 Therasense rejected and overruled the prior “sliding scale” approach to the two elements “where 

a weak showing of intent may be found sufficient based on a strong showing of materiality, and 

vice versa.” Id. at 1290. Therasense held that “a district court may not infer intent solely from 

materiality. Instead, a court must weigh the evidence of intent to deceive independent of its 

analysis of materiality.” Id.

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As to deceptive intent, Therasense held that “[t]o prevail on a claim of inequitable 

conduct, the accused infringer must prove that the patentee acted with the specific intent to 

deceive the PTO.” Id. at 1290. Therasense expressly rejected inequitable conduct based on the 

patentee’s alleged negligence or even gross negligence. See id. (“A finding that the 

misrepresentation or omission amounts to gross negligence or negligence under a ‘should have 

known’ standard does not satisfy this intent requirement”). “In a case involving nondisclosure 

of information, clear and convincing evidence must show that the applicant made a deliberate 

decision to withhold a known material reference.” See id. (original emphasis). “In other words, 

the accused infringer must prove by clear and convincing evidence that the applicant knew of the 

reference, knew that it was material, and made a deliberate decision to withhold it.” Id. 

Dropbox cites a single sentence from Therasense in its Response brief, where the court 

held that “a district court may infer intent from indirect and circumstantial evidence.” Id. at 1290 

(quoted in Response, Dkt. 235 at 3). But Dropbox fails to acknowledge the high evidentiary 

standards that Therasense imposed on an accused infringer’s use of indirect evidence to prove 

deceptive intent. In the very next sentence of the opinion, Therasense holds: “However, to meet 

the clear and convincing evidence standard, the specific intent to deceive must be the single most 

reasonable inference able to be drawn from the evidence.” Id. “Indeed, the evidence must be 

sufficient to require a finding of deceitful intent in the light of all the circumstances.” Id. 

(original emphasis). “Whenever evidence proffered to show either materiality or intent is 

susceptible of multiple reasonable inferences, a district court clearly errs in overlooking one 

inference in favor of another equally reasonable inference.” Id. (quoting Scanner Techs. Corp. v. 

ICOS Vision Sys. Corp., 528 F.3d 1365, 1376 (Fed. Cir. 2008)).3

3 Therasense further held that the patent owner is not required to offer any good faith explanation 

for the failure to disclose unless the accused infringer first proves a threshold level of deceptive 

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 8 of 15
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Therasense also tightened the legal standards for the materiality element of inequitable 

conduct. Therasense adopted a “but-for” standard for materiality and instructed district courts to 

“determine whether the PTO would have allowed the claim if it had been aware of the 

undisclosed reference.”4Id. at 1291. See also id. at 1294-95 (expressly rejecting the broader 

definition of materiality from the USPTO’s patent examination rules). 

Just as the Therasense court intended, the Federal Circuit’s tightening of the substantive 

standards for inequitable conduct have led to a dramatic increase in the number of cases in which 

the district court enters partial summary judgment against a defense of inequitable conduct prior 

to trial. Contrary to Dropbox’s statement of the legal standards, Therasense made it significantly 

more difficult for an accused infringer to survive summary judgment on a defense of inequitable 

conduct. See, e.g., DeCurtis LLC v. Carnival Corp., 2023 U.S. Dist. LEXIS 26590 at *22-30, 

2023 WL 2071915 (S.D. Fla. Feb. 8, 2023) (reviewing post-Therasense cases and discussing the 

impact of Therasense on summary judgment standards for inequitable conduct).

B. Dropbox Has Not Presented Evidence Sufficient to Create a Genuine Dispute 

of Fact Requiring a Trial on Inequitable Conduct

1. Dropbox Has Not Identified a Specific Reference or Any Specific 

Information that the Patent Applicant Allegedly Failed to Disclose

Dropbox’s inequitable conduct defense, as explained in its Response brief, is premised on 

the applicant’s and patent prosecutor’s alleged failure to disclose technical details regarding the 

functionality of the Dropbox system, as Dropbox existed at the time of the patent application. 

See Response, Dkt. 235 at 4. Critically, however, Dropbox fails to identify any specific Dropbox

intent by clear and convincing evidence, and that “[t]he absence of a good faith explanation for 

withholding a material reference does not, by itself, prove intent to deceive.” Id. at 1291.

4 Therasense recognized an exception to the but-for materiality requirement “in cases of 

affirmative misconduct.” Id. at 1292. But the exception does not apply where the inequitable 

conduct defense is based on an alleged failure to disclose, “[b]ecause neither mere nondisclosure 

of prior art references to the PTO nor failure to mention prior art references in an affidavit 

constitutes affirmative egregious misconduct . . . .” Id. at 1292-93.

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 9 of 15
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technical information that the patent applicant allegedly failed to disclose. Dropbox’s Response

brief makes repeated vague references to “Dropbox” or “Dropbox’s features,” with no additional 

specificity. See id. at 4-6. Dropbox does not identify any specific product manual, technical 

documentation, sales brochure, or other specific document that it contends the applicant should 

have disclosed to the USPTO. See id.

Dropbox’s failure to identify a specific technical document or specific technical 

information is fatal to its inequitable conduct defense. See, e.g, Golden Hour Data Sys. v. 

emsCharts, Inc., 2012 U.S. Dist LEXIS 114989, 2012 WL 3494366 (E.D. Tex. Aug. 15, 2012). 

2. Dropbox Has Not Presented Any Evidence that the Allegedly 

Undisclosed Information Was Material to Patentability

Dropbox makes no attempt to show that any allegedly unsubmitted Dropbox technical 

information would have been material to the patentability of any particular asserted patent claim, 

and Dropbox makes no attempt to show materiality by comparing, on an element-by-element 

basis, the allegedly unsubmitted prior art to any patent claim. Instead, the only evidence Dropbox 

cites in support of materiality is the testimony of its own expert, Dr. Shamos, who offers a 

conclusory opinion that “the allegedly infringing features of Dropbox were already in public use 

before the date of the asserted patents.”5 Response, Dkt. 235 at 5. 

Dr. Shamos’s testimony comparing the Accused Instrumentalities to the alleged prior art 

is a “practicing the prior art” defense that is forbidden under Federal Circuit law. See, e.g., 01 

Communique Lab., Inc. v. Citrix Sys. 889 F.3d 735, 742 (Fed. Cir. 2018) (“There is no 

‘practicing the prior art’ defense to literal infringement”). Dropbox is prohibited at trial from 

attempting to prove invalidity by comparing its accused products to an alleged prior art system, 

5 Motion Offense has submitted evidence contradicting this assertion by Dr. Shamos, but it need 

not itemize that proof here. “Practicing the prior art” is a legally prohibited defense, and any factual 

dispute regarding the similarities or differences between the Accused Instrumentalities and prior 

versions of the Dropbox system are legally irrelevant to this motion for summary judgment. 

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 10 of 15
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and the cited Dr. Shamos testimony is inadmissible. See Uniloc USA, Inc. v. Microsoft Corp., 

632 F.3d 1292, 1322-23 (Fed. Cir 2011); Zenith Elecs. Corp v. PDI Comm. Sys., Inc., 522 F.3d 

1348, 1363 (Fed. Cir. 2008). Dropbox cannot meet its summary judgment burden by relying on 

evidence that is not admissible at trial. See Fed. R. Civ. P. 56(c)(1)(B).

3. Dropbox Has Not Presented Any Evidence of Motion Offense’s 

Allegedly Deceitful Intent

As stated very plainly in its Response brief, Dropbox’s inequitable conduct defense is 

premised on a negligence or gross negligence theory of deceptive intent. See Response, Dkt. 235 

at 5 (“As users [of Dropbox], Mr. Morris, Mr. Gordon, and Mr. Zilka should have known about 

Dropbox’s features”). But Therasense expressly rejected negligence or gross negligence theories 

of inequitable conduct. See Therasense, 649 F.3d at 1290 (“A finding that the misrepresentation 

or omission amounts to gross negligence or negligence under a ‘should have known’ standard 

does not satisfy this intent requirement”).

To show deceptive intent under Therasense, the alleged infringer must show three things. 

“[T]he accused infringer must prove by clear and convincing evidence that the applicant knew of 

the reference, knew that it was material, and made a deliberate decision to withhold it.” Id. at 

1290. Dropbox has presented evidence showing none of these three requirements. 

Dropbox’s Response brief cites no evidence at all to show that the applicant or his 

attorneys had actual knowledge of the unspecified Dropbox technical details that Dropbox 

contends should have been submitted to the USPTO. Dropbox asserts only—with no supporting 

evidence—that the applicant “should have known” of unspecified technical details of Dropbox. 

See Response, Dkt. 235 at 5. Dropbox similarly points to no evidence at all that the applicant or 

his prosecution attorneys were actually aware that undisclosed technical details regarding 

Dropbox were material to patentability. Nor does Dropbox point to any evidence at all showing 

that the applicant or his attorneys acted with a specific intent to deceive the patent office. 

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 11 of 15
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“Proving that the applicant knew of a reference, should have known of its materiality, and 

decided not to submit it to the PTO does not prove specific intent to deceive.” Therasense, 649

F.3d at 1290.

The flimsy evidence cited by Dropbox comes nowhere close to raising a disputed fact 

issue requiring trial on the deceptive intent element of inequitable conduct. To survive summary 

judgment, Dropbox must produce evidence making deceptive intent “the single most reasonable 

inference to be drawn from the evidence” and the evidence must be so strong that it is “sufficient 

to require a finding of deceitful intent in the light of all the circumstances.” Id. at 1290.

“[W]here there are multiple reasonable inferences that may be drawn, intent to deceive cannot be 

found.” Id. at 1290-91. The evidence here supports a reasonable inference of no deceptive intent, 

and therefore the Court must grant partial summary judgment. See id. at 1290-91.6

II. PARTIAL SUMMARY JUDGMENT IS REQUIRED AGAINST DROPBOX’S

PROSECUTION HISTORY ESTOPPEL DEFENSE

Dropbox is correct that if the Court enters summary judgment against all of Motion 

Offense’s doctrine of equivalents theories of infringement, then the Court should also find that 

this motion is moot with respect to prosecution history estoppel. See Response, Dkt. 235 at 6. 

But the inverse is not true. If the Court denies Dropbox’s motion for summary judgment on the 

doctrine of equivalents, Dropbox is not automatically entitled to carry its prosecution history 

estoppel defense to trial. Dropbox bears the burden of proof on this defense, and thus Dropbox 

6

See also, e.g. Cao Lighting, Inc. v. Feit Elc. Co., 2023 U.S. Dist LEXIS 45494 at *12-13 (C.D. 

Cal. March 16, 2023) (granting summary judgment against inequitable conduct where the 

“evidence here does not establish inequitable conduct as the single most likely inference”); Tinnus 

Enters., LLC v. Telebrands Corp., 2017 U.S. Dist. LEXIS 219839 at *14-16, 2017 WL 8727626 

(E.D. Tex. Aug. 15, 2017) (granting summary judgment where accused infringer failed to show 

intent to deceive was the single most reasonable inference); Navico Int’l v. Garmin Int’l, 2017 U.S. 

Dist. LEXIS 136930 at *5-6 (E.D. Tex. Aug. 7, 2017) (same); Monkeymedia, Inc. v. Twentieth 

Century Fox Home Entm’t, LLC, 242 F.Supp.3d 551, 556-57 (W.D. Tex. 2017) (same); ROY-G 

BIV Corp. v. ABB, Ltd., 63 F.Supp.3d 690, 695 (E.D. Tex. 2014) (same).

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 12 of 15
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must present evidence supporting the defense to survive this motion for partial summary 

judgment. See Motion, Dkt. 198 at 2-3.

Dropbox’s Response cites no evidence at all to support its prosecution history estoppel 

defense. See Response, Dkt. 235 at 6. Indeed, Dropbox does not even articulate any specific 

theory of prosecution history estoppel. See id. Dropbox merely states, without further 

explanation, that “Dropbox’s prosecution history estoppel defense depends entirely on Motion 

Offense’s doctrine of equivalents allegations.” Id. This flippant statement, with no cited 

evidence, is insufficient to meet Dropbox’s summary judgment burden. 

Anything that Dropbox would say at trial on prosecution history estoppel would come as 

a complete surprise to Motion Offense. Dropbox has never articulated a specific theory or 

identified any evidence in support of this defense. Dropbox cannot sandbag Motion Offense and 

the Court in this way. The discovery rules and summary judgment procedures are intended to 

eliminate this type of surprise and ambush at trial. 

III. PARTIAL SUMMARY JUDGMENT IS REQUIRED AGAINST DROPBOX’S 

ENSNAREMENT DEFENSE

Dropbox is completely wrong to assert that Motion Offense bears any “initial burden” 

with respect to Dropbox’s ensnarement defense. See Response, Dkt. 235 at 6-7. When an 

accused infringer asserts ensnarement as an affirmative defense to an infringement claim based 

on the doctrine of equivalents, “the accused infringer bears the initial burden of producing 

evidence of ensnared prior art.” See Argina Tech. Ltd. v. Nissan Motor Co., 2022 U.S. Dist.

LEXIS 23489 at *10, 2022 WL 18046696 (E.D. Tex. Oct. 24, 2022) (citing Jang v. Boston Sci. 

Corp., 872 F.3d 1275, 1285 (Fed. Cir. 2017) and Interactive Pictures Corp. v. Infinite Pictures, 

Inc., 274 F.3d 1371, 1380 (Fed. Cir. 2001)).7

7 Dropbox points out that the Argina opinion was “a report and recommendation that was never 

adopted.” Response, Dkt. 235 at 6 n.4. In fact, this report and recommendation was neither

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 13 of 15
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Dropbox is wrong to suggest that its ensnarement defense can survive summary judgment 

because Motion Offense has failed to carry its “initial burden.” Motion Offense has no such 

burden—initially or otherwise. “The hypothetical claim analysis is not the only method in which 

a district court can assess whether a doctrine of equivalents theory ensnares the prior art.” Jang, 

872 F.3d at 1285 n.4. Because a patentee may rebut ensnarement in other ways, the patent owner

is under no general obligation to propose a hypothetical claim. This is particularly true where 

Dropbox has failed to meet its initial burden to identify a particular prior art reference that 

Dropbox contends is ensnared by Motion Offense’s use of the doctrine of equivalents. 

Again, Dropbox cannot be allowed to surprise Motion Offense at trial by revealing its 

ensnarement theory and evidence for the first time. Dropbox is correct that this motion for 

summary judgment is moot as to ensnarement if the Court grants summary judgment against 

Motion Offense’s use of doctrine of equivalents. But if the Court denies summary judgment on 

doctrine of equivalents, it still must enter partial summary judgment against Dropbox’s 

ensnarement defense because Dropbox has failed to meet its summary judgment burden to come 

forward with evidence supporting its own affirmative defense. 

objected to nor adopted because the case settled just four days later. See Joint Motion to Stay 

Deadlines and Notice of Settlement, Dkt. 337, Case No. 2:22-cv-00126 (E.D. Tex. Oct. 28, 2022). 

Dropbox does not identify any error in the reasoning or holding in the cited Argina order. 

Case 6:20-cv-00251-ADA Document 276 Filed 03/31/23 Page 14 of 15
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Dated: March 31, 2023

s/ Derek Dahlgren

Timothy Devlin (DE Bar No. 4241)

Alex Chan (Texas Bar No. 24108051)

Donald Puckett (Texas Bar No. 24013358)

Derek Dahlgren (pro hac vice)

Srikant Cheruvu pro hac vice)

Andrew Sherman (pro hac vice)

DEVLIN LAW FIRM LLC

1526 Gilpin Ave.,

Wilmington, DE 19806

Telephone: (302) 449-9010

tdevlin@devlinlawfirm.com

achan@devlinlawfirm.com

dpuckett@devlinlawfirm.com

ddahlgren@devlinlawfirm.com

scheruvu@devlinlawfirm.com

asherman@devlinlawfirm.com

ATTORNEYS FOR MOTION OFFENSE, LLC

CERTIFICATE OF SERVICE

I hereby certify that on March 31, 2023, I caused the foregoing to be electronically filed 

with the Clerk of the Court using CM/ECF, which will send notification of such filing to all 

registered participants.

/s/ Derek Dahlgren

Derek Dahlgren

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