Can't move text box over image in impress or drawing

Hi, I’ve pasted an image, set it to “protect size and position”. Then I add a text box by clicking the text box icon. A cursor appears in the middle of the screen (not where I want it on the image) and I can type, but there are no grab handles on the text box. When I finish typing, I click outside the text, then mouse over the text box, but still there are no grab handles, and nothing happens if I click on the text and try to move it with the mouse (touchpad). I tried the same in both Impress and Drawing - same problem in both. Thanks in advance!

No problem here (using LibreOffice on Linux) - when hovering the mouse over the text box, the cursor changes its appearance and at that moment just click and move (or drag on the squares at the corners or the four sides of the text box to resize the text box)

That’s the thing. On my Mac (OS Mojave) the corner squares don’t show up, and if I click and move the image behind the text moves and not the text.