SQLyog Enterprise v5.2 Beta 1
I've been able to reproduce this bug consistently.
I perform a simple query (i.e. SELECT * FROM [table]). Some of the results will be TEXT. SQL shows the first part of the element and then has a block showing the total size of that element.
When I click on the element to see the full content of the TEXT element the edit window opens up blank and “SET NULL” is checked (these TEXT fields are set to NOT NULL and confirmed in an Alter Table view).
If I try uncheck the SET NULL check box, SQLyog will crash (close out instantly).
Note: This only happens in the RESULT table, not the TABLE DATA tab