QUESTION
 How can I change pushbutton enablement when text is entered
 in a textbox?

ANSWER
 There are several ways to go about doing this depending on what
 you'd like to happen.  I'll give two very basic examples below.

 The first example starts off with a text box and a pushbutton
 that's initialized as disabled.  You can disable a pushbutton
 initially by going into the settings for the pushbutton and removing
 the check mark next to the enabled box. Disable the pushbutton before
 making the following connection.  Connect the object event
 of the text box to the enabled action of the pushbutton.  Then
 go into the settings of the connection, select the set parameters
 button, and set the value to true (ie - check the value box).
 This causes the pushbutton to be disabled until any text is entered
 in the text box.  The pushbutton then remains enabled.  If you
 want the pushbutton to again become disabled for whatever
 reason, you would have to write script for that.  Which leads to
 the next example...

 The second example starts off exactly like the first example.  The
 view contains a textbox and a disabled pushbutton.  This
 pushbutton will remain disabled until text is entered into the text
 box and the text box loses focus (like tabbing out of it...).  As soon
 as the text box loses focus with text entered into it, the pushbutton
 becomes enabled.   If you then go back to the textbox, delete the
 text, and tab out of it, then the pushbutton becomes disabled again
 and will remain disabled until text is entered into the text box.  This
 is accomplished by writing a small script in VisualAge that looks
 like this:

 enableButton

        | info |

        info := ((self subpartNamed: 'Text') string).

        (info isEmpty)
        ifTrue: [(self subpartNamed: 'Push Button') enabled: false]
        ifFalse: [(self subpartNamed: 'Push Button') enabled: true].

 You would connect the losingFocus event of the text box to this script.