Hello.
a - Using Affinity Photo 1.9.0.932 after automatic update. Windows 20H2 (19042.746, experiencePack 120.2212.551.0).
b - Having no custom keyboard shortcut, working on a fresh new file.
1 - Problem : The SPACE BAR does not permit to move the selection while selecting (M : Rectangular Marquee Tool and consors).
- How to reproduce : Open AP, File>New... choose any format (say 800x600). Press M to select the Rectangular selection Marquee tool. Drag to make a selection -> WITHOUT releasing the left mouse button, press the space bar to move the location of the selection = > Nothing happens.
- Workaround : None.
2 - Problem : SHIFT does not permit to ADD a selection.
- How to reproduce : Open AP, File>New... Choose any format (Say 800x600). Press M to select the Rectangular selection Marquee tool. Make a selection. Once done (release the mouse), try to ADD another selection by keeping SHIFT pressed. The little "+" does not appear beside the mouse. A contrario, pressing ALT does well permit to remove a part of selection (the little "-" beside the mouse appears).
-Workaround : Set the selection tool to "Add" and not to "New" (Default), then you can add/remove with SHIFT/ALT.
Thank you for reading. If you have any question, don't hesitate.
Cédric.