Disable drag & drop attachment upload when modal dialog is shown

Review Request #10108 — Created July 29, 2018 and updated — Latest diff uploaded

Information

Review Board
release-3.0.x
c6a4dba...

Reviewers

The previous behavior could be very annoying when trying to update a
diff using drag & drop. Also, when using the "Add File" dialog the
behavior was confusing.

Chose "Update Diff", dragged file onto browser window
-> drag & drop overlay did not appear
Chose "Add File", dragged file onto browser window
-> drag & drop overlay did not appear
Dragged file onto review request view (Reviews/Diff)
-> drag & drop overlay appeared