Testing on xfce 4.8pre2 over fedora 14 with http://repos.fedorapeople.org/repos/cwickert/xfce-4.8/ packages. 1. Xfce starts from scratch (Original panel configuration). =>. I get a pager with 4 desktops in a row. 2. I go to the properties page, change the number of rows to 2. Expected: 2 rows of 2 virtual desktops. Result: Continues to show a row of 4 virtual desktops. Ps: without "show miniatura view" option, it works correctly.
Do you have > 1 pager in the panel, could you check if the panel leaves any information in the terminal (you could see this with 'xfce4-panel -q', and then start the panel in a terminal window with 'xfce4-panel'). The problem lies within libwnck, that also tries to change the actually workspace layout in the window manager, not only the appearance of the pager plugin.
[matias@localhost ~]$ xfce4-panel -q [matias@localhost ~]$ xfce4-panel libpager-Message: Failed to set the number of pager rows. You probably have more then 1 pager in your panel setup. libpager-Message: Failed to set the number of pager rows. You probably have more then 1 pager in your panel setup. The last two messages are when change the value, and to clarify that I have no other pager. The problem is not expressly of libwnck. With xfce4.6 and 4.4 worked fine. Now.. "actually workspace layout in the window manager, not only the appearance of the pager plugin."? This is correct and should work this way. What is wrong, is that a simple plugin control the behavior and distribution of an entire desktop. We have a dialogue, xfwm4-workspace-settings, which is responsible for setting the number of virtual desktops. But a simple plugin is responsible of workspace layout. In this way, the plugin seems to have "more power" than the desktop configurator. Even more.. Xfwm has the xfconf entry of the number of desktops, but the configuration of rows depends on xfce4-panel/plugin/pager. I think, xfwm4-workspace-settings should configure the workspace layout. No the pager!. If you are interested, I can try to make a patch about it. Regards. Matias.
To be clear, this is something in a non-xfce library and I've already filed a bug about this in the Gnome bugtracker. https://bugzilla.gnome.org/show_bug.cgi?id=635341
Nothing I can do about this, wnck issue.
I have discovered a workaround for this, I think. I found this bug report because of: https://bugzilla.redhat.com/show_bug.cgi?id=728975 My issue: Unable to use keyboard shortcuts to go up/down in my 2-row workspace layout. Workaround: Toggle miniature view twice. I was using label names, but toggling mini view on/off immediately fixed my problem.
I have a similar problem in xfce4-panel-4.10.0-2.fc18.x86_64 (Fedora 18): I have dual-head setup, and a separate panel near the bottom of each screen, each panel with its own pager (this is for convenience only, each pager shows both heads). Pagers are set up as 3x3 virtual desktops. When I log in, one of the pager is displayed as expected, and the other one has only one row of virtual desktops (i.e. 1x9 instead of 3x3). Right-clicking on the pager and selecting Properties make it immediately switch to 3x3 layout - I don't need to toggle miniature view off and back on, as described in comment #5. I have also added a new comment to GNOME bug #635341, but I don't know XFCE4 code enough to describe what is wrong with libwnck (if any). So I am not sure whether to reopen this bug or the GNOME bug (which has a request for clarification in the comments, and the original reporter did not respond to it). Please, XFCE developers, can you take over the discussion with libwnck developers?
Jan: I created https://bugzilla.xfce.org/show_bug.cgi?id=11831 for that case; multiple monitors, multiply identical configured pagers.