I don’t think this can be done in Potlatch (although I may be mistaken), however in JOSM this is quite easy to do in two ways:
In selection mode: use the left-click-and-drag mouse action to select all the ways and nodes you want to move. ‘Grab’ the selection (left-click and hold), move to the desired position and unselect by clicking somewhere on the map.
In selection mode: select the outer way (the lake) using the left-mouse button. Hold the shift key and left click the island. Both ways should now be selected. Carefully hover the mouse pointer over one of the selected ways, but not in the middle of the way!, then left-click and hold and move the selection to the desired position. Unselect by clicking somewhere on the map.
A bit cryptic perhaps but very easy when you’ve done it a few times.
In Potlach 2 you may choose several objects to be moved at the same time. First you click at an object (in this case the lake), then hold down the CTRL key when clicking on more objects (in this case islands). Now it’s easy to move both the lake and it’s islands at the same time.
Brilliant so I will think of adding islands after I have am about through with lakes. Or tarns or pools or what ever.
Anyway, now getting up enough information that I am ready to work on the Garmin 62s issues. I have added a few peaks and tracks. Now we are talking “vast untracked areas” so on the small Garmin 62s screen it is hard to find things unless they appear at the higher levels. Now lakes are great as they appear at high levels but mountains and walking tracks do not They only appear at 300 metres zoom which you have to be right on top of them to find them. Ok, for a track I might live with this but not for mountains nor huts.
Actually be good to have tracks, huts and mountains appear when further zoomed out than 300 metres. In the areas I am talking they are not going to clash with roads or other objects. So what are the options?
Still, be careful. I own a 62s and much to my disappointment, I found that sometimes it can be several meters off!
Ugh, this is one of my biggest gripes about the tiny screen on the 62s and the way it hides certain features - say, when I want to plan which way to go to some feature far away, I can’t both see the feature on the map and the paths that lead to it. One option may be to use self-baked raster maps: