#jira UE-16413 - Applying materials to BSP takes a long time once shells reach a basic level of complexity
Previously, setting a material or its texture transform on a BSP surface triggered CommitModelSurfaces, which iterated all the ModelComponents in the level and caused (among other things) the physics state to be recreated, a very expensive operation. This is clearly unnecessary when only the surface material or texture transform has changed, so introduced a new path in which only the Material Index Buffers are updated for the level's UModel.
[CL 2613582 by Richard TalbotWatkin in Main branch]
#jira UE-16765 - Details panel is blank when selecting BSP surfaces if 'Clicking BSP Enables Brush' is disabled.
[CL 2584208 by Richard TalbotWatkin in Main branch]
The display name, filter string, and tooltips for the property editor (and associated detail customizations) are now stored as FText rather than FString. This allows us to remove SLATE_TEXT_ARGUMENT from the detail customization widgets.
[CL 2372595 by Jamie Dale in Main branch]
