This task should be simple but apparently isn't:
I want to add a layer with three lines of text to an image; the text needs to be centered vertically and horizontally relative to the image as a whole.
The web is full of suggestions that I seem to be misusing.
I can create a layer with the text, and autocrop it to just the text, but when I select the layer and choose the align tool the buttons on the align tool are either grayed out or seem to have no effect, whether I select the layer contents or not.
I've been expanding the layer boundary to the size of the image with the contents, but that does not work consistently.
(My goal is to create a set of simple buttons, with a shared element and different text and background for each button.)
(GIMP 2.8.16 on a Mac)