UI: Delete selection dialogs when parent is deleted

[cg2121]

Description

In the source context bar, when an user opens a selection dialog
(font, color or file), and they switch scenes (causing the source
toolbar to be deleted), OBS would crash, as the dialog is no longer
valid. This is fixed by deleting the dialog when the toolbar is
deleted.

Motivation and Context

Fixes #7824

How Has This Been Tested?

Made sure the selection dialogs were deleted when switching scenes.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[WizardCM]

Unfortunately this only fixes the crash with hotkeys. It'll still occur when switching scenes via WebSocket or third party plugins/scripts. The better way to fix this would be by properly using the relevant dialog constructors rather than the helper functions, and automatically closing the dialog during the destruction of the toolbar.

[cg2121]

Updated it to delete the selection dialogs, when scenes are switched.

[CodeYan01]

While this is about the toolbar, i've seen this happen with my media playlist plugin that creates an editable list property. i have code that will use obs_source_update_properties when the video has ended (as i want the property to show the file name of the current file in the editable list). if one were to add file/folder/url and have the dialog open while the video ends (thereby calling that code that calls obs_source_update_properties), obs crashes with a similar QT crash log. It also happens if the user is dragging an item in the list while the obs_source_update_properties is called. Of course, this is due to the properties being recreated, and what I did is likely unsupported (and I have since removed the obs_source_update_properties call when the video ends), but I wanted to mention it anyway.

[PatTheMav]

Could it be that this is a Windows-specific issue? Because in my tests the file browser, font picker, and colour picker are all modal dialogs, so I cannot even change the scene.

Or did we fix this in the meantime - @gxalpha does this ring a bell?

[cg2121]

It happens when you switch scenes with hotkeys.

[PatTheMav]

It happens when you switch scenes with hotkeys.

Thanks, got it to crash. It also blocked keyboard input in all other applications, which is even worse..

I do wonder if the easier fix would be to ignore hotkeys affecting the main window when a modal window is open. Allowing hotkeys to affect the underlying (blocked) Window seems wrong and runs counter to the idea of a modal dialog.

[cg2121]

Closing in favor of #9981