That's a problem I had reported to the author of Taskbar3. Apparently there's some problems with this module when running with the 0.24.7 betas (the one you're using is the beta 3 version that comes with the Installer 2.5). It seens that is a problem with LS 024.7 and not with the taskbar3. I'm waiting to move to 024.7 just because of this problem. If you use the latest Indie Build you'll have no problems like this.
Hope that helps