There's a useful feature in Windows where a window that requires the user's attention but is not selected (or is minimized) gets highlighted and becomes red on the taskbar until clicked. This is commonly seen on open messenger Windows that are minimized / deselected, when the other person messages you.

I noticed this doesn't work for Pidgin with KDE's task manager, so I was wondering if there's any way to enable the feature. Or if the feature doesn't exist, are there any plans to implement it?

The feature in KDE exists, but the client (pidgin) has to mark itself "urgent" (by setting the ICCCM flag, also KWin will tag it urgent when it attempts to activate itself and that is suppressed)
It's nothing that could be done from outside (only pidgin knows that it got a message)

There's a chance that pidgin doesn't notice that it's minimized because that is (optionally) only "emulated" with an active compositor (so that the minimized window will still update it's content in previews)
run "kcmshell4 kwincompositing" and in the last tab ensure "Keep window thumbnails" is NOT "Always (breaks minimization)"

Other than that, you'll have to file a bug against pidgin to mark itself urgent whenever it feels like (at least if the highlight in general works, could also be a general bug in the taskmanager)

That's good. I don't remember seeing the feature work with any window, and I think Pidgin did this under Windows 7 (but I don't remember well). I also think it doesn't work when the window is not minimized but just unfocused.

As for that setting, I went to Desktop Effects - Advanced and "Keep window thumbnails" is set to "Only for Shown Windows", which I think is the default.

what pidgin does or does not on windows doesn't matter - there's no guarantee it does this (correctly) on Linux/X11

The window manager will mark the window urgent when it attempts a raise and is suppressed in that, but it think that's it.

kopete or IRC clients like quassel should have similar (and configurable) functionality (highlight the task item when there's a new -private- message)
does it work with them?

Just tested with my IRC client (KVirc) and it actually works. But the effect on highlighted windows is so discrete I had to look closely to notice it (only the blue border around the taskbar entry brightens). Would be nice if the next version of KDE would add some blinking to that, or the default desktop theme could make this more visible. It also won't keep the panel from auto-hiding, which I'm not sure if it's a functionality I prefer or not.

To get it to work with Pidgin, you can go to Tools -> Plugins, enable Message Notification, Configure Plugin -> check "Set window manager "URGENT" hint".

The taskbar flashing effect depends on the Plasma Theme, as far as I remember it's pretty clear with the default Air theme.

Hans wrote:To get it to work with Pidgin, you can go to Tools -> Plugins, enable Message Notification, Configure Plugin -> check "Set window manager "URGENT" hint".

The taskbar flashing effect depends on the Plasma Theme, as far as I remember it's pretty clear with the default Air theme.

Thanks, enabled that as well. But yeah, they're very subtle in KDE 4.8.5 with the default Air theme... and I have the default theme fully enabled. Wonder why this is for me. No flashing effect for me either.