In Settings / Global settings, you can enable output notification. This feature notifies you, when something arrives from the MUD. There are two different sorts of notification, global and local.

Global notification takes effect when the KMuddy window is inactive and some text arrives from any of the MUD servers you're connected to. It causes the window caption and the appropriate field in the taskbar to start flashing. Note that in KDE 3.0 and below, this is done by showing and hiding some stars ('*'),since flashing isn't supported. It keeps flashing until you activate the KMuddy window.

Local notification works similarly, but it only applies to one connection. When it is not active and some new text arrives, the caption in the tab bar on the top of KMuddy window starts flashing in the same way as with global notification. It keeps flashing until you switch to that connection. This flashing never happens for the active connection, so keep this in mind when using both local and global notification (some text may have arrived to the active connection; even if its tab is not flashing).