In a protected cell, if you click on text then the cursor is entered, double-clicking to select a word does not select anything. Triple-clicking selects the entire sentence which is frequently the entire contents of the cell. Quadruple-clicking selects the paragraph as expected but in this case it can be difficult to know whether you are triple or quadruple clicking. OP did say “entire text outline” not cell contents (everything inside cell border).
Simplicity suggests the table cells are protected. It is all academic of course as OP has moved on now but might help someone in a similar predicament.