I don’t know anything about qt. But I can criticise the design a bit. If something isn’t possible to realize in qt then I apologise.

1. The Label may not need to be displayed in a separate line. You maybe could put the basic information abpu the window into the windows title and display additional information from the label when hovering over the title.
2. The sliders have no way to display what the concrete value selected with the slider is. You may want to include the concrete value next to the slider name.
3. The 3 buttons in the windows top box could be reduced. From a use case perspective being able to hide the tool window and then restore it at the same position is the same as being able to collapse it.
4. A kind of spacer between the sliders and the next sliders name could make it faster to identify which slider belongs to which name. Don’t know what would look good but you could try leaving a tiny bit more space between them or including some thin lines that don’t touch the windows edges.