I'm seeing similar issues with the following version:
Build ID: RADO97-I20181109_1539
For me, I can click on items in the UI but the content for most of the default views fail to load. As I click or hover over tabs. they will "dissappear" and there are a number of "Unhandled event loop exception" errors against org.eclipse.ui in the Workspace Log view. Also, the application hangs if I try to resize the window.
Is there a version that has been tested with Big Sur?#RationalApplicationDeveloper(RAD)#Support#SupportMigration