This patch tries to harmonize the drawing of //UILists// and the new //"Tree view"// row buttons:
* They now share their theme settings, under `User interface -> List Item`
* UILists buttons are now drawn only when selected or on hover, as it's currently done for the "Tree View"
Also included in the patch is a way to highlight text in the selected tree row, placed inside the loop of `TreeViewLayoutBuilder::polish_layout()`.
{F12808881}