1) Open a Copyholder window. 2) Click into the main portion of the editor to make it active 3) Close the Copyholder window with the "X" in the header bar 4) Switch to a different document in the Binder
The Copyholder window will reopen on its own.
Two further observations:
--This bug does NOT occur if you skip Step 2 above (in other words, when you have clicked into / made active the text in the Copyholder window). --The same bug will occur if, instead of clicking "X" to close the Copyholder window, you click the icon next to the "X" (to simultaneously close the Copyholder window and open the document in a Quick Reference Panel)