Sample Points keep resetting themselves to "Pixel"
Using GIMP 2.10.5 from git updated yesterday on Gentoo Linux:
I put 12 Sample Points in the Sample Points dialog and changed each Sample Point from displaying "Pixel" to displaying "LCh". Then I added several layers, put a mask with a horizontal stripe in the middle on one layer, and used Levels to attempt to make the LCh "L" values in the masked image match the LCh "L" values in the underlying layer.
At some point all the Sample Points reset themselves from showing "LCh" to showing "Pixel" values, requiring that I reset all of them again from "Pixels" to "LCh". This happened several times during this editing session. This isn't new behavior, it's been a problem for awhile now - the user-chosen color space for the Sample Points just keeps getting reset to "Pixel" values.
I reset all the Sample Points to LCh, saved the document as an XCF file, closed it, and reopened it. Upon reopening the XCF file, all the Sample Points were reset to "Pixel".
In the particular use case for which I added 12 LCh Sample Points, the document was just a set of 21 blocks with L values L=0, L=5, . . . L=95, L-100. My specific goal was to make a Curves preset that could be used to modify tonality in actual image files. Another common use case for setting Sample points to something other than "Pixel" is to monitor shadows and highlights, along with specific important areas in an image, for example if one wanted to set the sky at roughly L=50.
Regarding 1. above, for people who habitually want to see LAB or LCh or HSV or whatever, it would be nice to have an options in Preferences to specify "Use Color space X" for Sample Points, to avoid having to make this sort of change every single time a new Sample Point is added.
Regarding 2. above, having the Sample Points reset themselves during editing adds considerable extra steps for anyone who's trying to use Sample Points to make or monitor changes to an image.
Regarding 3. above, it would be nice if each XCF file saved to disk could remember what color space(s) the various Sample Points were using when the document was saved.
Possibly related to #1402 ?