SUMMARY I'm not sure how to succinctly summarize this, I think the steps to reproduce would explain it better. STEPS TO REPRODUCE 1. Select Basic-5_Size 2. Select Size option 3. Enable Fuzzy Dab sensor, select it 4. Select Pressure sensor 5. Close and reopen the brush settings OBSERVED RESULT You will be shown the Fuzzy Dab screen instead of the Pressure screen, the screen you left off at. EXPECTED RESULT To be shown the sensor you left off at, in this case Pressure. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Debian sid (available in About System) KDE Plasma Version: 5.17.5 KDE Frameworks Version: 5.70.0 Qt Version: 5.12.8 (Appimage) ADDITIONAL INFORMATION This makes it quite annoying to configure the sensors of a particular option when not sharing the curves, if you keep reopening the brush settings to test the brush on the canvas. Often I realize I'm configuring the Fuzzy Dab curve when I actually mean to configure the Speed curve for example. I am not using the scratchpad in this case due to https://bugs.kde.org/show_bug.cgi?id=425124 In the above steps to reproduce, even if you don't explicitly select Fuzzy Dab, and only enable it, you'll still be shown Fuzzy Dab when reopening the brush settings. The steps to reproduce are consistent, but in other cases I'm not sure what determines the logic of what sensor is remembered when you reopen the brush settings with other combinations. It's as if there is some methodical randomness to it but I'm not sure if it matters. Quite the awkward misfeature in the GUI.
I can confirm this for the 4.2.0 appimage and the latest Aug18 4.4.0 alpha (git c6ac82b) appimages. There is a pattern to the behaviour, with interesting exceptions (which may be stylus capability related) and an exception to the exceptions. I'm not going to bother describing them.
Another case where this is annoying is when directly comparing the curves of two brushes. One brush having Fuzzy Dab will make it very annoying to compare the two Pressure curves when swapping between the brushes, as said brush will keep showing you the Fuzzy Dab curve when swapping to it.