Hi,
I also asked this question to the technical support and got the following answer which solves the problem:
"...
I was able to reproduce the issue in R2014b based on your instructions. I found that the edit box disappears when the text string has multiple lines in and the box is too small to display them all. In the "MinimalExample.fig" you sent, the edit box string is "blub" then two empty lines. Removing those lines made the edit text box visible again.
The file exchange question you linked to is symptomatic of some underlying problem with GUIDE and the new R2014b graphics system, which we are still investigating. I'm not sure if your problem is related, since I was also able to replicate this behaviour in R2014a, although it does seem similar.
I will continue to look into this issue with our developers, but as a workaround you can remove the trailing whitespace from the Edit Text string or make the Edit Text boxes large enough to hold the string.
..."
Best Answer