Add way for plugin to specify label for quick open
Merge with master
Made optional arg handling more consistent in Quick Open plugin API
Clean up various dialog label code paths. Don't set the label before the first call to filter.
Allow plugins that don't care about language to work when no documents are open
fix 5742: It should pop up Error opening file dialog if click the image which is deleted from OS.
Updated by ALF automation.
Merge remote-tracking branch 'upstream/master'
refactor to share directory searching code used by working set
increment i before comparing with array length
Merge branch 'master' into couzteau/fix-5742-Error-on-deleted-img

Conflicts:
	src/editor/ImageViewer.js
Merge remote-tracking branch 'upstream/master'
#5800 fix
review feedback - removed the need for  ImageViewer or other CustomViewers to display a warning when an image is renamed or deleted while viewed.
remove unused modules from require section
remove unused var
hide guides when modal bar opens
Do not show error when file is deleted or renamed, instead just close image and open alternate file. Made this change to stay consistent with how text files behave in the same situation as well as to avoid a clunky error message.
Updated by ALF automation.
Guard against possible errors in ScopeManager.

These errors don't seem likely in normal use, but we're seeing intermittent failure
on the test machine which could be related.