I am having the same problem as the original poster. The text pane selector is visible as shown by Paul for about three seconds after opening the Tinderbox document in question and then disappears (as seen in the OP’s screenshot).
Which attribute controls this behaviour and how can one make the selector visible again?
The selector is not control by an attribute – it is part of the menu command structure. I posted the command above:
Window > Show / Hide Text Pane Selector
If you wish, you can add a shortcut to macOS to control this. Navigate to System Preferences > Keyboard > Shortcuts > App Shortcuts. Click the + sign. Add a shortcut for Tinderbox for Show Text Pane Selector and then add a separate shortcut for Hide Text Pane Selector. See more info from Apple here.
Oh dear, I asked another silly question.
In my defence, I did search for the command in aTbref and the Tinderbox help box but must have omitted the space (English is not my first language).
Many thanks for your continued assistance, Paul.