Checkboxes have a third, "grayed selection" state, which usually means "partial selection," especially in checkbox hierarchies. When using Gtk apps with Breeze theme in KDE environment, grayed checkboxes in Tree widgets only show their third state when corresponding Tree Item is selected. Additionally, third state isn't visualized even for a selected item when mouse is hovering over it. Third state isn't visualized for all unselected Tree Items. Standalone tri-state checkboxes (i.e. buttons with the checkbox style) don't show their third state in any condition.
My enviromnent: Linux Mint KDE 18.1 Plasma 5.8.5 Gtk 3.18.9 Gtk app: Eclipse 4.6 with custom plugin, Java UI library is SWT 4.6 (which uses Gtk).
Created attachment 104406 [details] example This is a screenshot of 2 rows in a Tree with checkboxes. Both of the checkboxes are in a grayed state but only selected item properly shows it. Additionally, if i hovered the mouse over selected item it would also show incorrectly.
Created attachment 104409 [details] Reproduction using Eclipse's standard dialog Just now found these simple repro steps: 1. Launch any type of Eclipse package. 2. Select Help - Install New Software... from the menu. 3. In the dialog's Work with field choose The Eclipse Project Updates site. 4. In the tree below, expand any node and select any one sub-node out of a set. This puts the parent-node's checkbox into grayed state. 5. However, grayed state is shown only when that parent-node is selected and not hovered on. In the screenshot parent "Eclipse Platform SDK" node is actually grayed.
Fixed now!