UETOOL-213 - Minimize Slate FString -> FText conversion (remove SLATE_TEXT_ATTRIBUTE)
This fixes any editor/engine specific code that was passing text to Slate as FString rather than FText.
[CL 2399803 by Jamie Dale in Main branch]
Added display of asset/class info used to Add Content dialog
Fixed several cut/pasted comments regarding UMG styles that referred to shooter game
[CL 2392502 by bruce nesbit in Main branch]
+ Fix text flicker on tab switch.
+ Don't allow multiple instances of the dialog to be opened.
+ Change the tab order to match the new project dialog.
+ Fix warnings.
[CL 2386074 by Frank Fella in Main branch]
+ Refresh feature packs automatically when they change on disk.
+ Remove drag and drop and batch install, and replace it with a single button for installing in the details section.
+ Don't allow multiple copies of the dialog to be opened.
+ Fix a missing brush visible when resizing the dialog.
+ Fix an issue where brushes in the dialog could get deleted resulting in white images.
[CL 2385434 by Frank Fella in Main branch]
