In high dpi mode, when a CSS pixel is more than one physical pixel, tree widgets containing text in system fonts have the rows double the height they should be. Steps to reproduce: 1. start firefox on a fresh profile 2. go to about:config and set layout.css.dpi to 192 3. look at about:config Actual results: Each row in the tree has the text in a system font (at the system font's size, which is correct), but there's a lot of extra whitespace around the text as though the font had been doubled in size. Expected results: the tree widget should appear without extra space

Quote from chrome://global/skin/tree.css: treechildren::-moz-tree-row { border: 1px solid transparent; min-height: 18px; height: 1.3em; } That seems likely to cause issues...

Hrm, maybe it's not so bad, then. I suppose that's there for images that go in trees?

Tree rows used to have fixed height of 18px and they didn't scale with size of fonts. I fixed it by adding min-height and height: 1.3em

(In reply to comment #3) > Tree rows used to have fixed height of 18px and they didn't scale with size of > fonts. I fixed it by adding min-height and height: 1.3em What exactly do you mean by "used to"? Is there some patch somewhere I'm missing? Or some non-default theme? All 5 instances of tree.css in the tree contain min-height: 18px.

I fixed it very long ago (several years). There must be a patch somewhere in bugzilla. The bug was assigned to me. I think the tree widget code, method GetRowHeight() should be adjusted to count with scaled CSS pixels.

My patch to bug 386640 appears to solve this.

I don't think anyone is going to work on this given the plan to remove the XUL "tree" widget (bug 1446335).