These commands are displayed only if a text layer is present.
In the Text to Selection drop-down list, the commands are identical to those of the Transparency sub-menu (in fact, the text is formed of areas of different transparency):
Text to Selection: Secció 7.38, «Alpha to Selection»
Add to Selection: Secció 7.39, «Add Alpha channel to Selection»
Subtract from Selection: Secció 7.40, «Subtract from Selection»
Intersect with Selection: Secció 7.41, «Intersect Alpha channel with Selection»