The issue is that ComboBox InputTextPlaceholder not working with If Formula.
Refer the screenshot below.

The cell highlighted with Orange is a Text box and so reads the IF formula and shows "Not Applicable" whenever it's cell is disabled. The problem with ComboBox (highlighted with Green) is that it shows BLANK for the same formula.
It works with IF formula only when i place this formula in NoSelectionText property instead of InputTextPlaceholder and also turn the IsSearchable property to "False".
I cannot do the later as it's a search based Person Type data card.
Please suggest a workaround. I would like to show different text based on whether it's editable or disabled.
Thanks