That bug is a bit difficult to describe, hope I can explain it well. I experience this bug with SIM, a KDE app. I've not tested it with other apps because I don't know other apps which require this functionality. First of all, when I start the application, it shows a select profile screen, which does not appear on the taskbar, while it does appear in gnome and kde's taskbars. The more serious "bug": SIM is a multi-IM client. It works similar to GAIM, using one window for contacts and one for messages. In the messages window, you have a tab for each contact you are in conversation with. Whenever you switch tabs, SIM changes the window title, according to the name of the contact, and the window icon, according to the user's protocol and status. The problem is, the taskbar does not update the window icon accordingly (meaning you can end up with an offline icon for an online contact, an ICQ icon for an MSN contact etc.). This bug exists with and without enabling KDE support in the session manager. The icons switched fine in xfce4. I hope I was understood, Thanks in advance.
1) can you load the "select profile" screen, then open a terminal and run the "xprop" command. it will turn the cursor into a crosshair "+" shape. click on the "select profile" window, and xprop will print out details of the window. please attach them to this bug (it'll likely be large, please attach, not paste into the comments box). 2) gaim does something similar: as you switch between different conversation tabs in a single window, it will change the window's icon to match that user's buddy icon, or, failing that, a protocol-specific icon. xftaskbar4 correctly notices this change, so it's possible SIM is using an incorrect or nonstandard method to change the icon. for future reference; one bug per bug report, please. also, please try a more descriptive summary "a bug in xftaskbar4" is not very useful: obviously it's a bug, else it wouldn't be here.
Created attachment 89 xprop output on SIM's "select profile" screen
I'm very sorry for the non-informative summary of the bug. I've no idea why but I just couldn't think of a normal summary at the time, guess I was too busy trying to describe the bug in detail. As for the way SIM changes it's icons, I've really no idea. All I do know is that it did work as it should in XFce 4.0.x. I've attached the xprop output above, as requested. Thank you.
hmm, i'm not sure, but i think xfce's taskbar is set up to not show buttons for modal dialogs. since they're modal, clicking on the button for their parent window will bring it to the top anyway. olivier, can you confirm this? if so, please mark this WONTFIX. regarding, the icon setting problem, i'm relatively sure this works as it should, so it's likely an app bug.
Yeap MODALS that specify a transient_for value aren't shown in the taskbar. Taht's because they "belong" to another window.