SWT.Settings event not fired for theme change - Gtk implementation

[fedejeanne]

Originally posted by @fedejeanne in eclipse-platform/eclipse.platform.ui#3138 (comment)

It would be nice to have a notification that tells the user that the High Contrast mode has been activated and offers him to restart the application. This already happens on Windows:

Here's the code that shows the dialog:

https://github.com/eclipse-platform/eclipse.platform.ui/blob/4a2727c448db22f5ebf7fad65987b100007de72e/bundles/org.eclipse.ui.ide.application/src/org/eclipse/ui/internal/ide/application/IDEWorkbenchAdvisor.java#L318-L333

How to test
Activate the High Contrast setting in the OS. A proper SWT.Settings event should be fired and (if you're using Eclipse) the dialog offering to restart the application should appear.

On Mac the dialog will not appear until the method org.eclipse.swt.widgets.Display.getHighContrast() returns something other than false.

[akurtakov]

For the record - Runtime theme change doesn't seem to "fire" settings event on Gtk. That would have to be fixed on SWT side.

[fedejeanne]

Thank you @akurtakov! You're right, I moved it to SWT.

I'm guessing this is also needed in Mac. Maybe someone could quickly test it? @BeckerWdf / @opcoach ?