text entry triggers

I want the students to attempt an answer in a text entry area and then be able to click a button taking them to the correct answer.  I don't want the button trigger to be activated until the student has at least made an attempt.  I have managed to accomplish this previously using the 'true' variable for the text box but I must have just stumbled on the method because I can't seem to replicate it.  I have      created a trigger allowing the layer to be shown when the text entry variable equals 'true'.  I have created a trigger on the button directing it to show the layer when the variable equals true.  I have set the text entry equal to the typed value of 'true'.  I just don't get it.  It's not working.

Any help appreciated.

Mary