Adding a new file for deletion while opening the about dialog causes the main window to "freeze"

[Muhammad Azeez]

If you add files for deletion while the about dialog is open, you can't do anything with the main window. That's because the main window waits for the about window to close and the about window gets behind the main window.

Steps to reproduce the bug:

• Open the about Dialog
• Add some files to be deleted (either by drag'n'drop or by Send To)
• The Confirmation dialog shows up
• Now you can't interact with the main window anymore