Fix: Add Text and Add Image dlgs were opening up in upper left, partially off screen [6025]
Bug Number: 6025
Release notes (y/n): Yes
For Release Nums: 7.1.5 and 7.2

Some special processing we were doing in the dialog's "ShowEvent" handling 
which was causing this problem.  It's not clear why.  Specifically calling 
QWidget::resize(), for a "last minute" dialog size adjustment being done in 
the ShowEvent processing is apparently a problem.  [This is with Qt 5.5.1].
The fix is to defer the call to resize() using a QTimer.

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