Original setup slowly drifts back to Desktop 1

[TopDex]

I set up the first two desktops
Desktop 1 General
Desktop 2 Imaging Photo MP3

The other 2 desktops are lying 'fallow'.

After 4 months usage, Desktop 2 icons are now (save for one)
all appearing on the extreme RHS of Desktop 1 (no screen-resolution
changes involved). Desktop 2 remains with one original icon in place,
which seems happy to stay permanently in the top left-hand position.

How to account for this? Must I physically, every so often,
re-position all icons from Desktop 2 back to Desktop 1?