In the image editor e.g. contrast/brightness tool, color tool, saturation tool, etc, many progress bars go from -100 to +100, and start at 0 (default value), but the bar itself is empty. It should be 50% filled. This is probably a junior job (thus JJ:) since easy to fix. But it is confusing at first. ;)
This problem ist only valid for the Fusion style. This sliders comming from the Krita project. Here is used a progressbar as slider. In the Fusion style has the value 0 no representation. Maik
Git commit 526dca606434131ac4b8f621bbe890fe14ac2533 by Maik Qualmann. Committed on 28/01/2017 at 20:55. Pushed by mqualmann into branch 'master'. fix Fusion style from the DAbstractSliderSpinBox FIXED-IN: 5.5.0 M +2 -1 NEWS M +2 -2 libs/widgets/common/dsliderspinbox.cpp https://commits.kde.org/digikam/526dca606434131ac4b8f621bbe890fe14ac2533