OS X and applications sometimes don't respond to keyboard commands

Today I started having problems with using keyboard shortcuts in MacOS X 10.6.5.

However I could not figure out the concrete circumstances when this problem appears.

I realized it the first time, when the Finder did not respond any more to keyboard commands.

The Apple key seemed to have no effect. None of the usual shortcuts worked, however I could use the mouse normally.

Suddenly it worked again.

This happened again several times - also in other applications.

The applications I'm currently using:

TexMakerX (= TeXstudio)

Skim

Freeplane 1.2.8

Notational Velocity

Safari

Minuteur

Terminal

DevonThink Pro Office

Quicksilver B60.

As I invoke Quicksilver with a single hit on the command key, I often realized that something was wrong, when the Quicksilver window did not appear.

However, last time when that happened I could use a trigger Ctrl-Alt-Cmd-M to invoke the Quicksilver window with a certain command, but I was not able to invoke the standard Quicksilver window with command alone...

I sometimes (?!) could even not the small process window with Cmd-Alt-Esc to see if some applications was hanging.

This is very strange - did anyone encounter similar problems?

I've been testing, during the last days, Optimal Layout and today upgraded the trial version to the most recent one. Maybe it is OL which causes those problems?

How can I figure out what happens, when the computer is suddenly blocked?

Kind regards

beckmart

Message was edited by: beckmart