Slate : Waiting on Draw Buffer

Development Rendering
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1

When I test the game and try and open a particular widget the editor/game hangs,
including the log but after I press escape it recovers and ends the game and I can see there are hundreds of messages saying

LogSlate: Warning: Slate: Had to block on waiting for a draw buffer.

Everything was working fine and this just suddenly started happening and I have no idea what the issue is. Any ideas as to what the message might mean?

2

this message is quite confusing! and for my case, it was caused by breakpoints in slate widget blueprints! After I delete all breakpoints in BP, this message disappear!