In order to create the graphics that you see in the design view, Designer
creates an off screen window containing the various widgets and they takes a screen snapshot of them. This works very well under Windows, OSX and some versions of Linux. Recent versions of the Metacity
window manager (more recent than 2.1.4), however, have been modified/"fixed" to disallow windows to be opened off screen. This forces the preview window to appear on screen leading to an annoying flashing effect any time you make a change. The solution is to disable the Metacity
"fully_onscreen" constraint by patching the Metacity
source code and rebuilding and installing the patched version into your system.
Here are the steps to follow (from the Designer FAQ
1) Download the Metacity
source code from ftp://ftp.gnome.org/pub/gnome/sources/metacity/
2) Unpack the source code tarball into any temporary directory.
3) Chdir into this directory (with the unpacked code).
4) Find window.c
file and open it with your favourite texteditor.
5) Find a line with "window->require_fully_onscreen = TRUE;
6) Replace it with "window->require_fully_onscreen = FALSE;
7) Save the changes and close the editor.
8) Open a terminal and chdir into the directory with the source code (nice if you have already done this)
9) Run "./configure
10) Run "make all
11) Make sure that steps 9 & 10 completed without errors.
12) Become root (or execute the next command via "sudo" depending on the Linux you are running)
13) Run "make install
" (or "sudo make install
14) Save your work and close any application you are working with.
15) End your session (or press Ctrl-Alt-Delete to restart the x-server) and log in again.
16) You are done!