Bug 576197

Summary:	Improve "Argument not valid" message for disposed parent containers
Product:	[Eclipse Project] Platform	Reporter:	Lars Vogel <Lars.Vogel>
Component:	SWT	Assignee:	Platform-SWT-Inbox <platform-swt-inbox>
Status:	NEW ---	QA Contact:
Severity:	normal
Priority:	P3
Version:	4.22
Target Milestone:	---
Hardware:	PC
OS:	Windows 10
Whiteboard:

Description Lars Vogel

2021-09-22 10:05:19 EDT

Currently if I create a widget on a disposed container I get:

"Argument not valid"

Would it be possible to return a message which is a bit more helpful? For null parameter I get:

Caused by: java.lang.IllegalArgumentException: Argument cannot be null

Maybe we could add a new exception for argument is disposed and return it in Widget#checkParent?

Currently:

if (parent.isDisposed ()) error (SWT.ERROR_INVALID_ARGUMENT);