Move a selected section (or brushstroke) exactly horizontal or vertical only

I would often like to have an option in the crop tool, for example, to be able to press an additional button so that I can move a selected section exactly horizontally or vertically with the mouse without accidentally shaking it in the other direction. In some programs this can be done with the Shift key. I hope I haven’t overlooked something and this possibility already exists.

Hi Ralf,
have mentioned this missing (basic) feature multiple times.

To ‘draw’ (paint) a straight line with the manual brush / eraser e.g. in PS one clicks for the starting point, then to press & hold Shift and continues clicking … so simple.

Depending on the brushes feathering one gets harder or softer edges. And with a couple of shorter straight lines (strokes) one can paint ‘curved’ lines to refine such selections.

Yeah, this feature request already exists: