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Bug 345210

Summary:	Text in CLabel does not display unless "Disable Preview Window flickering workaround (Linux only)" is selected.
Product:	z_Archived	Reporter:	Jim Mayer <jim>
Component:	WindowBuilder	Assignee:	Alexander Mitin <Alexander.Mitin>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	normal
Priority:	P3	CC:	clayberg
Version:	unspecified
Target Milestone:	---
Hardware:	PC
OS:	Linux
Whiteboard:

Description Jim Mayer

2011-05-09 17:42:06 EDT

Build Identifier: 20110218-0911

In a CLabel control, text does not seem to display unless the "Disable Preview Window flickering workaround (Linux  only)" WindowBuilder option is set.  This happens on my 64 bit Linux system running a 32 bit verison of java:

$ java -version
java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
Java HotSpot(TM) Server VM (build 19.1-b02, mixed mode)

$ uname -srvmpio
Linux 2.6.32.26-175.fc12.x86_64 #1 SMP Wed Dec 1 21:39:34 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux




Reproducible: Always

Steps to Reproduce:
1.Make sure that the "WindowBuilder>Disable Preview Window flickering workaround (Linux  only)" preference is not checked.
2.Create a new SWT/JFace project.
3.Create a new SWT Application window.
4.Switch to design view and add a "CLabel" control.  Give it some text.
5.Observe that the text does not display.
6.Select the "WindowBuilder>Disable Preview Window flickering workaround (Linux  only)" check box.
7.Close and reopen the SWT Application window.
8.Observe that the label text appears.

Comment 1 Alexander Mitin

2011-05-16 19:04:02 EDT

This is not a WindowBuilder bug. Under the hood the WindowBuilder renders UI into the real window (to provide a real look and feel of the designing UI). After UI rendered, we take a screenshot of the preview window and then display it for you. We move the preview window into offscreen area, but Linux window managers are very 'smart' and don't allow the window to move there resulting annoying flickering. Under Linux, the 'preview window flickering' is the big problem, for the long time. We've tried many different tricks and workarounds but none of them works 100%. So, if something displays incorrectly, just set disable preview window flickering workarounds option.

Comment 2 Eric Clayberg

2011-05-16 19:40:43 EDT

This is basically a Linux window manager issue that will vary from one Linux distro to another and one version to another.

Comment 3 Jim Mayer

2011-05-17 14:39:08 EDT

(In reply to comment #2)
> This is basically a Linux window manager issue that will vary from one Linux
> distro to another and one version to another.

Thanks for looking into this.  I think I understand what you're saying, and can even guess as to why some of the widgets display just fine with the flickering workaround and other's don't.  It doesn't really matter though.

My one suggestion would be that you record the problematic behavior in a "linux issues" section and have the "Disable Preview Window flickering workaround" text point people there.  I only discovered the checkbox by accident.  If the issue had been described in a "linux issues" section I wouldn't have posted the bug report and you wouldn't have had to answer it!

This is a good product that is filling a real need.  I very much appreciate the work you're putting into it.