I've found a interesting bug in the lastest version (7.55 32bit 17.6.2010). Here's how to reproduce:
* open total commander

* use the internal viewer to open any text file
* search for an string that will not be found
* A dialog tells you that the string was not found. DO NOT CLOSE IT!!!
* Go back to the main TC view and try pressing TAB to switch "panels" - it doesn't work
* Open another internal viewer on any other file and try pressing ESC to close the viewer - that also doesn't work
Basically, as long as the "Not found" dialog is there, you cannot really use the keyboard anymore.
Cheers
Loris