Those functions I mentioned are standard Tcl/Tk functions. In the 8000rc1 release I added some more explanations about handling variables with the global prefix ::.
Unfortunately I do very little Tcl/Tk stuff myself, so I depend on users like you pointing out specific problems they run into when interfacing with newLISP. This is how the 'scale' example got in to the manual showing how to work around a specific callback problem.
Before you told us that the :: prefix could be used, I didn't even know about it and tried to solve the problem doing a 'global varName' in each tk statement, which also works, but is kind of clumsy. I have the :: - technique now included in the manual.
Lutz