Excel (Office 365 ProPlus) : Active X TextBox not working correctly

julelui : yes, I replaced it with a normal text box, which worked for my requirements.
Even though I lock my excel, I can type into this text box by unclicking the "lock text" property under "format". However, this is of cause not the solution for the initial problem - nevertheless, I hope it helps

julelui I think I've managed to find the root cause of my issue - it turned out that using a secondary monitor with duplicate display setting was the reason, however I have not identified why so only resolution I found so far is to unplug the extended display