Thanks. Yes, it's clear... unfortunately there are a few buts.
Drag-drop is known; how else do you think I was managing ordering market watches? The problem is that on exit, this ordering of scrips does not always get saved. Once it sticks, you are all set till the next time you have to add / remove / rearrange symbols.
Ctrl-M is the command to set the default market watch; will try it nonetheless if it works even if it is not the thing wanted.
The only sure thing I'm aware of is 'Save Groups'. But, rearrange a market-watch and go to Groups -- the rearranged order is not reflected there.