Is the TextDisplay an Indicator?
So a front panel can have Indicators [Message, Record] and a TextDisplay.
The TextDisplay and any Indicators are optional. EC-1470 added a method to see if the TextDisplay was fitted which would have a knock on effect if someone tried to reserve the TextDisplay via the Indicator APIs.
But in the file fp.properties you've added text as a valid indicator. I don't think it is an Indicator at all.
I would expect the Platform to say 'Yes, I have a TextDisplay' but that's not an Indicator you would set m_textDisplayPresent as true, but not add it to the m_supportedIndicators collection.
So simply put, fp.properties shouldn't have text as an indicator and some of the logic for processing the presence and access of the TextDisplay need addressing.