Operating System: Windows 10 (64-bit) / Linux Mint 19.1 (64-bit)
OS version/build: Kernel 4.15.0-47-generic (Linux)
GPU: GeForce GTX 1050 Ti/PCIe/SSE2
GPU drivers: 398.36 (Windows), 390.116 (Linux)
The Alfisko skin does not always update sliders' background (the little bar behind the knob):
Dragging another slider forces the background of the previous slider to be updated correctly, but then the dragged one would also produce the artifacts.
The issue retains on both tested platforms (Windows & Linux), with OpenGL rendering backend & SDL2.
It seems like Alfisko is the only skin having "dynamic" slider backgrounds which also updates with the knob position, as the other themes with static backgrounds do not exhibit the issue.
Compile CEGUI with
Select AlfiskoSkin from the skin drop-down, and choose one of the slider variant (
Dragging around the slider a few times.