Why's the Text Menu Disabled?
Because you haven't selected a text object to play with. Click on any text you've added to your label. This will make it the selected object, and it will grow a red sizing frame & titlebar, and a toolbar will appear underneath it. Now the Text menu should be enabled, and choices you make from this menu (excluding the "Create a new text object" option) will apply to the text you've selected.
If you don't have any text on your label, try clicking on the "Text" button on the main toolbar or selecting the "Create a new text object" item from this menu to add some.