This has always worked fine for me, up to the point I enabled desktop effects in KDE. 
Chromium slows down as soon as a tab becomes detached and crashes afterwards. When I 
restart Chromium, I get two windows: my original window and a window with the detached 
tab.

On the console, I see this error:

The program 'chromium' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 33338 error_code 3 request_code 137 minor_code 6)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)

I also have this problem but it only started happening after changing to the new 
"nouveau" driver in fedora.  I don't have effects enabled (they don't work in the 
nouveau driver)

I have this problem both with "nouveau" and with "vesa".
5.0.375.99 beta

For me, this is not technically a crash, but it makes X unusable.  If I switch to a tty console, wait 2 minutes for it to appear, kill chrome, and return to X, all is fine.

This issue has been closed for some time. No one will pay attention to new comments.
If you are seeing this bug or have new data, please click New Issue to start a new bug.