Keyboard modifiers are being detected as pressed permanently erroneously (Environment variable editor navigation is broken with keyboard)

It is not possible to use arrow keys and home/end inside the Environment variable editor fields. The reason for this is that the modifier keys (alt, ctrl, shift, winkey) are sometimes detected as being pressed erroneously.

Comment by reactosfanboy:

The following reproduction steps do not guarantee to trigger it, but will work about 40-50% of the tries, eventually they are enough to create and verify a fix

• Select "My Computer" on desktop with arrow keys
• Hit Alt+Enter to open properties dialog
• Navigate into the environment variables dlg and edit a variable by just using mouse
• Try to use arrow-left/arrow-right/home/end

In case those keys do not work, then you triggered the bug.

Another faster way to reproduce:

• Select "My Computer" on desktop with mouse
• Hit Alt+Enter to open its properties
• Hit Esc to close properties window
• Hit Enter key to open "My Computer"
• Expected: My Computer window opens
• Observed: System Properties window opens

Maybe it would be even more comfortable to test using some kind of software that displays current pressed modifier keys.
Attached screenshot that shows the dialog affected by bug.

The bug is present since more than a year already (build 0.4.9-RC-35-g3eb03ef is affected), it's unknown whether it ever worked properly.

Still actual in 0.4.15-dev-5286-g885459d8b43.