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Widget event handlers

In a widget program [TranslateAxies] I am writing I specify an event 
handler function for each widget that can generate an event.  I specify 
event handlers for each text and button widget but not for base and 
label widgets [no bases are resizeable].  No base widgets can be 
resized.  The GUI includes text boxes for user input.  When I ran the 
program initially, put text in any box and clicked enter,  I always got 
the error:
Attempt to call undefined procedure/function: 'TRANSLATEAXIES_EVENT'.

So I put a do-nothing procedure with this name in the 
TranslateAxies_EventCB file.  Now I do not get the error.  Also, all the 
text widgets and their event functions seem to run fine [when I click 
return after entering a value in the text field], because their values 
in the info structure are updated OK. 

It does not seem like I need this do-nothing proceedure.  Can anyone 
tell me why it is needed?

Also, when I type text in a text widget it will not call the event 
function to update the value in the info structure if I click tab to 
move out of the field.  Why is this?

Joseph E. Means
Assistant Professor,  joe.means@orst.edu
Department of Forest Science
Oregon State University
Corvallis, OR 97331-5752