Merge #3914 Add test to check GUI thread safety #1323

Job	Run time
build_NetCore (Debug_NetCore)	1m 3s
build_NetCore (Debug_NetCore)	1m 3s
build (6.8, Debug)	1m 34s
build (6.8, Debug)	1m 36s
build_NetCore (Release_NetCore)	1m 8s
build_NetCore (Release_NetCore)	1m 8s
build (6.8, Release)	2m 28s
build (6.8, Release)	2m 28s
build (6.10, Debug)	1m 33s
build (6.10, Debug)	1m 33s
build (6.10, Release)	1m 38s
build (6.10, Release)	1m 38s
build (6.12, Debug)	2m 12s
build (6.12, Debug)	2m 12s
build (6.12, Release)	1m 58s
build (6.12, Release)	1m 58s
build (latest, Debug)	2m 2s
build (latest, Debug)	2m 2s
build (latest, Release)	2m 46s
build (latest, Release)	2m 46s
	36m 46s

Provide feedback