Bug 553787

Summary: Default to disable Redraw in AbstractTreeViewer#expandToLevel and expandAll
Product: [Eclipse Project] Platform Reporter: Lars Vogel <Lars.Vogel>
Component: UIAssignee: Lars Vogel <Lars.Vogel>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: P3 CC: karsten.thoms, Lars.Vogel, paul-eclipse
Version: 4.14Keywords: noteworthy, performance
Target Milestone: 4.15 M1   
Hardware: PC   
OS: Linux   
See Also: https://git.eclipse.org/r/153857
https://git.eclipse.org/c/platform/eclipse.platform.ui.git/commit/?id=e8a6608fbfded4488c1a4014585aec7efb59c1f2
Whiteboard:
Bug Depends on:    
Bug Blocks: 553533    

Description Lars Vogel CLA 2019-12-04 18:10:52 EST 
We have many bugs in which the tree expand was slow before redrawn was not enabled. See Bug 522335 or Bug 543737.

I suggest to change the default to redraw false, if the user does not specify a value.
Comment 1 Eclipse Genie CLA 2019-12-04 18:14:54 EST 
New Gerrit change created: https://git.eclipse.org/r/153857
Comment 2 Lars Vogel CLA 2019-12-04 18:16:09 EST 
Noticed this while looking at Pauls change in https://git.eclipse.org/r/#/c/153853/. 

Any concerns here?
Comment 3 Karsten Thoms CLA 2019-12-09 07:12:28 EST 
How shall we identify clients that would like to have redrawing while expanding a tree? I'm not sure which are those use cases. In many cases the user would like to have a faster result. But how this behaves, for example, in the project explorer?
Some unwanted behavorial changes might be detected during a release iteration when this gets enabled early. I assume in most cases disabling the redraw while expand/collapse should be better.
Comment 4 Lars Vogel CLA 2019-12-09 08:05:09 EST 
(In reply to Karsten Thoms from comment #3)
> How shall we identify clients that would like to have redrawing while
> expanding a tree? I'm not sure which are those use cases. In many cases the
> user would like to have a faster result. But how this behaves, for example,
> in the project explorer?
> Some unwanted behavorial changes might be detected during a release
> iteration when this gets enabled early. I assume in most cases disabling the
> redraw while expand/collapse should be better.

Definitely not something for 4.14 but for 4.15. I hope nobody relies on slow drawing operation, if someone does we can reconsider.
Comment 5 Lars Vogel CLA 2019-12-09 08:09:32 EST 
(In reply to Karsten Thoms from comment #3)
> How shall we identify clients that would like to have redrawing while
> expanding a tree? I'm not sure which are those use cases. In many cases the
> user would like to have a faster result. But how this behaves, for example,
> in the project explorer?
> Some unwanted behavorial changes might be detected during a release
> iteration when this gets enabled early. I assume in most cases disabling the
> redraw while expand/collapse should be better.

It might also fix multiple issues, see for example Bug 442621 which will be fixed by a turned of return in collapse.
Comment 6 Karsten Thoms CLA 2019-12-09 08:33:33 EST 
You asked for concerns, and this came to my mind ;) We should give it a try for early 4.15.
Comment 7 Lars Vogel CLA 2019-12-09 08:35:04 EST 
(In reply to Karsten Thoms from comment #6)
> You asked for concerns, and this came to my mind ;) We should give it a try
> for early 4.15.

Indeed, I did. Thanks. :-)