Hi Andre,
I have been getting this window from time to time.  Here are the steps I use to reproduce it.
1.  Close Twistpad if opened
2.  Open Twistpad
3.  Drag and drop a file on Twistpad
4.  With the file now opened, I do a control-f to bring up the Find window
5.  I type in a term to search for
6.  Click More -> Find All
More times than not following these steps brings up the window in the attached image.
After I click OK, everything is fine and I can continue working on the document.  If I close the document and then proceed starting at step 3, I do *not* get the pop up window.
