Office 365/Excel, I did the following:
But when out of design mode and selecting the textbox to type, the cursor is not showing - that is, no invitation to type anything. If I type something in G1, that value appears in the textbox. If I type something in the textbox, the characters are invisible in the textbox but appear dynamically in G1, and then appear in the textbox when I click outside the textbox.
Also, if I format textbox to change the order to something else (say "bring to front"), I can type in the textbox OK, but when I click outside, the behaviour returns.
I read somewhere a textbox is bi-directional and this appears to be so, except for being unable to see the characters typed in the textbox.
Wondering if you're using external monitors?
There seems to be a bug in Excel and I had the exact same issue. As soon as I unplugged the second monitor or (actually just moving the Excel document to the main screen, the ActiveX textbox was working as intended).
Hope that helps.