Suggestion for a new "fence" option for selection tools
Operating System: Xubuntu 22.04.1
Description of the feature
For various editing operations such a clone, sharpen, levels, hue, etc. you can use a selection to limit the area where the edit is applied.
I would like to suggest that something similar, which I will call a "fence" be implemented to restrict where selections themselves can be applied. For example, If you are selecting using the color tool or fuzzy select, it would be great if you could constrain where the selection would be applied. This is the idea of the fence. In its simplest form, it could be just the visible area on the screen limited by zooming into a region. But ideally it could be set/modified in the same way that the rectangular, ellipse or free select tools allow. This fence option could be placed on each of the selection tool menus and would be off by default. There could be a toggle where you go into/out of fence mode and constrain the region where further selections would be restricted. Possible this region could be outlined in some high-contrast color, or maybe the region outside of the fence could be greyed out to indicate that that area was currently inactive. A "clear fence" button would allow the fence to be quickly removed.
Use cases
An example of why this might be useful: In landscape shots I often need to select the sky from the other content so that it can possibly be blurred slightly but definitely not sharpened along with everything else. In low contrast cases, this can be an involved operation that requires zooming in to the sky/land border and making fine selections using the fuzzy or color tools. I often find that when I zoom back out, a lot more than I bargained for has also been selected. If the zoomed view (or a rectangular region) was first fenced, then you could make the selection with confidence that there were not going to be any future surprises.
I hope that description was clear. Would others find something along these lines useful?