Sounds like we're making progress on this one. We still need some more data to pin this down. For everyone who is experiencing this problem, we could use the information from the profiler.
Please be sure to reset the value for def_actapp to its previous value before running this procedure.
1) Launch SlickEdit as normal and open any workspaces and files that seem to trigger the slow response.
2) Turn on the profiler. From the SlickEdit command line, run: profile on.
3) Switch to another application.
4) Switch back to SlickEdit.
5) Wait for normal responsiveness to return.
6) Turn off the profiler. From the SlickEdit command line, run: profile save "profile.txt"
7) Post the resulting "profile.txt" file.
Please try to do as little as possible while the profiler is running so that the times reported reflect what is being done after switching back to SlickEdit. Thanks for your help with this.