Bug 574472

Summary:	ClassCastException in PartRenderingEngine.subscribeVisibilityHandler() during startup of RCP application
Product:	[Eclipse Project] Platform	Reporter:	Ron Anderson <rwa5908>
Component:	UI	Assignee:	Platform-UI-Inbox <Platform-UI-Inbox>
Status:	NEW ---	QA Contact:
Severity:	normal
Priority:	P3
Version:	4.17
Target Milestone:	---
Hardware:	PC
OS:	Linux
Whiteboard:

Description Ron Anderson

2021-06-25 11:18:07 EDT

Our RCP based application is throwing ClassCastExceptions in PartRenderingEngine.subscribeVisibilityHandler() during startup.

ContributedPartRenderer.getUIContainer() is returning a Rectangle which is being cast to a Composite causing the error. 

This appears to be related to restoring the workbench layout from a previous invocation since it doesn't happen on the first execution after removing the .metadata/.plugins/org.eclipse.e4.workbench/workbench.xmi