How to find out the vanished test scripts of a particular test set in a test lab of the QC. How to bring them to the normal view as before.
It's difficult to answer this question as each Q.C. installation uses different settings, but my approach would be to check that I have no active filters in Test Lab, after that I would make sure that I can see ALL columns in the Execution Grid. My final thing to check is that when I click on Select Tests button the Test Plan Tree listview is visible and contains the test folders (and scripts) from my Test Plan module - of course you should check that you have no active filters in the listview.
If that doesn't work can you provide actual screen shots of your Test Plan module and your Test Lab module?
Let me know if that doesn't work - if not I'll take a look at your SQL in the link, but it does look complicated for what you're asking.
Hope this helps,