Clicking on Item in Task Manager mimizes other active apps

For a little over a week I’ve been bugged by what I suspect is a setting that I’ve somehow inadvertantly changed. I’m trying to key information into an OpenOffice spreadsheet that is being viewed in another application, typically Firefox. Both windows are sized such that they fit on the screen at the same time. Prior to a week or so ago, this was very straight forward. Now when I click on an app in the Task Manager after opening OpenOffice, other open apps are minimized - sometimes all of them, sometimes just the most recent. I usually have Dolphin, a terminal window, Firefox, OpenOffice and sometimes a spreadsheet open. A friend who is far more familiar with Linux than I, suggested that the memory manager may have gotten confused and that logging out should clear this up. I tried that to no avail, as well as rebooting. I’ve also looked through the options in each of the apps that I’ve got open to see if there’s any obvious user options that might be affecting this. I’ve found nothing.

Anyone have an idea what might be going on and how to correct it?

You did not say which Desktop KDE or Gnome.

If KDE there is a setting in personal setting that will do that I believe. Forget exactly where though.

KDE is the desktop that I’m using