You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 14/162,381 filed on Jan. 23, 2014. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a system for installing corner trim on a building or structure with a system of brackets that are hidden from view and that obviate the need for cleanup of fastener holes. 
     BACKGROUND 
     In the conventional manner of applying corner trim to a building structure the installer has already completed the installation of paneling to the wall and brought the edges of the from the two sides of the corner as close to the corner as time and costs permit. The installer then cuts a first length of trim to be applied in a vertical orientation to the corner to obscure the first side of the corner. The installer then cuts a second piece of trim to length for abutting the first panel which approaches the corner from the opposite side of the building. The principle two principal reasons for securing corner trim to a building is to obscure the gap between the oppositely approaching siding panels and to prevent the intrusion of moisture to surfaces that can be degraded by exposure to moisture. An open gap between the abutting siding lengths may lead to water intrusion underneath the siding that could result in wood rot, mold growth and ultimately structural damage to the building. Moreover, should high speed wind apply back pressure to a siding length at the gap, the resulting pressure on the siding could tear the siding loose from the structure. Additionally, corner trim provides a much more attractive appearance than closely butted siding members and serves to enhance the aesthetic appeal of the structure. 
     In a typical application described above the installer secures the oppositely approaching boards to the building surface with screws or nails. It is the process of passing nails or screws through the boards into the building structure that depressions are created in the surface where the nails or screws have passed that either are preferably retouched with a water-proof filling compound to create a smooth surface. The filled surface is then painted to create an unblemished appearance. It will be appreciated that these additional steps are time consuming and add additional cost to the installation. 
     Unfortunately, and particularly in regions of the country where there are temperature extremes and/or high humidity, the hardened water proof filling compound over time is often expunged either partially or fully from the fill hole because of expansion and contraction of the siding panels due to temperature changes or the absorption of moisture that causes the siding boards to swell when damp and contract when ambient moisture recedes. This expungement of the putty creates an unsightly appearance that then requires additional costly maintenance to remedy. 
     Even when the highest skill level is used to secure the siding boards to the structure small gaps or uneven end cuts can result. This less than desirable outcome can efficiently and cost effectively be remedied with the application of the disclosed corner trim system. 
     An object of the present invention is to provide trim that can be attached to a building corner in a manner that does not require driving attachment hardware through the front face of the trim. 
     For the foregoing reasons, there is a need for a trim system utilizing a hidden bracket system that does not require the use of any exposed fasters to secure the trim to the building. 
     These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims, and appended drawings. The contents of this summary section are provided only as a simplified introduction to the disclosure, and are not intended to be used to limit the scope of the appended claims. 
     SUMMARY 
     This disclosure relates to a concealed fastening building finishing element system that enables concealed fastening of corner trim to an underlying structure. The trim serves both an aesthetic purpose in adding a decorative feature to building envelopes and also adds an additional weatherproofing purpose in allowing for more complete weatherproofing of building envelope corners and openings. 
     In accordance with one aspect of the disclosure, there is provided a concealed corner trim system including trim members, each trim member having a structure-facing surface and an exterior-facing surface. 
     The invention advantageously allows the use of standard fastening guns and standard commercially available fasteners. This advantageously results in minimum cost of implementation and minimum additional skills required for installers. 
     Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawings in which like numerals represent like components. The contents of this summary section are provided only as a simplified introduction to the disclosure, and are not intended to be used to limit the scope of the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary hidden bracket and a partially completed corner trim member installation in accordance with an exemplary embodiment; and 
         FIG. 2  illustrates a plan view of an exemplary embodiment of a bracket engaged with a trim member. 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIG. 1 , which reveals a building corner  11 , siding panels  13  with panel end edges  15  secured in position atop wall materials  17 . The wall materials  17  come together at joint  19  forming the corner  11  of the building  21 . The hidden bracket corner system  30  shown as partially installed, is comprised of a bracket  32  and trim pieces  34 . 
       FIG. 2  reveals an exemplary first embodiment of the bracket and panel system.  FIG. 2  illustrates a cross section, or plan view, of the trim piece  34  secured to the bracket  32 . The bracket and trim are preferably fabricated from a durable and rigid engineered plastic, or resin; however, metal and ceramic brackets and trim are also contemplated. The bracket  32  is comprised of first and second orthogonally disposed panel elements  36 ,  38  each with an outboard end  40 ,  42 . The panels are joined at centerline  44 . At least one flange  46 ,  48  extends outwardly from each of the outboard ends  40 ,  42  of the first and second orthogonally disposed panel elements  36 ,  38 . At least one locking tooth  54 ,  56  extends outwardly from each of the flanges  46 ,  48 . 
       FIG. 2  also reveals, in cross section, the trim piece  34  that is attachable to the bracket  32 . The trim  34  includes a first and second outer face surface  60 ,  62 , a first and second hidden surface  64 ,  66  facing the building, and a cutout  68 ,  70  on each side of the trim piece proximate the first and second hidden surfaces. The cutouts  68 ,  70  are comprised of overhangs  72 ,  74  that serve to shield the potentially rough cut edges  15  of the siding panels  13  from view by an onlooker. The overhangs  72 ,  74  are preferably no thicker than 0.25 inches and extend no further than 0.75 inches from the cutout face surfaces  76 ,  78 .  FIG. 2  also reveals at least one longitudinally extending slot  80 ,  82  disposed within each of the first and second trim piece hidden face surfaces  64 ,  66  for receiving the at least one flange  46 ,  48  extending outwardly from the outboard ends  40 ,  42  of the first and second orthogonally disposed panel elements  36 ,  38 . 
     The flanges  46 ,  48  are preferably canted away from the plane of the panel elements  36 ,  38  at an angle in the range of from 120 to 150 degrees and preferably at 135 degrees. The bracket  32  may optionally include a weather strip  50 ,  52  that extends outwardly from the hidden surfaces facing the structure  64 ,  66 . The weather stripping  50 ,  52  serves to prevent the intrusion of moisture beneath the siding panels  13 , or trim piece  34 , and are flexible yet resilient. The weather stripping  50 ,  52  may optionally be secured to the trim  34  with an adhesive or formed as part of the fabrication of the trim and preferably extends a distance consistent with the overhangs  72 ,  74 . 
     In operation, as best seen in  FIG. 1 , the embodiment of the bracket  32  is positioned over the joint  19  of the building corner  11 . The bracket  32  is then secured in position by passing screws or nails through the holes  90  in the orthogonally disposed panel elements  36 ,  38 . Once an appropriate number of brackets  32  are in position atop the building corner  11  the trim piece or pieces  34  may be snapped into position. To accomplish securing the trim  34  to the bracket  32  the trim piece  34  is placed atop the bracket with the longitudinally extending slots  80 ,  82  of the trim piece aligned with the outwardly extending flanges  46 ,  48  of the bracket. Sufficient pressure must be applied to the surface of the trim to allow the flanges  46 ,  48  with their locking teeth  54 ,  56  to fully traverse to the top of the longitudinally extending slots  80 ,  82 . Once the flanges  46 ,  48  are inserted into the slots  80 ,  82  to the desire depth, the trim pieces are secured in position and because the locking teeth will bite into the walls of the slots  80 ,  82  there will be limited opportunity to reposition the trim  34 . 
     While the preferred form of the present invention has been shown and described above, it should be apparent to those skilled in the art that the subject invention is not limited by the figures and that the scope of the invention includes modifications, variations and equivalents which fall within the scope of the attached claims. Moreover, it should be understood that the individual components of the invention include equivalent embodiments without departing from the spirit of this invention. 
     It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. Not all steps listed in the various figures need be carried out in the specific order described.

Summary:
A system for installing trim installations at external corners of a building includes trim and a bracket. The trim serves both an aesthetic purpose in adding a decorative feature to building envelopes and also adds an additional weatherproofing purpose in allowing for more complete weatherproofing of building envelope corners and openings. The disclosed system relates to a concealed fastening building finishing element system that enables concealed fastening of finishing trim.