[improvement] The git tree selection is difficult to read

[kawazoe]

Describe the bug While not a bug specifically, the theme doesn't handle the complexities of the git tree view very well. To my knowledge, it is the only list in the IDE that has multiple kind of highlights. While lists usually highlight the selected item, the git tree highlights commits in the current branch as well as the current selection. Using the same background color for those two states makes it difficult to distinguish between the two, even if the text color changes. This problem is exacerbated when a selection in the tree view is made, and then the focus is moved to an other element, as the unfocused+selected state colors are the same as the focused+current-branch colors.

To Reproduce Steps to reproduce the behavior:

1. Open any git repository with multiple branches in the IDE.
2. Open the "Git" toolbox and try the following selection patterns in the tree view:

• none
• select a few consecutive commits at the tip of a branch
• select a few consecutive commits across branches

Screenshots All screenshots taken with the Octagon variant.

This screenshot was taken with no selection made.

This screenshot was taken with the tip of the current branch selected. If the list is not in focus, this selection is indistinguishable from the previous screenshot.

This screenshot was taken with a selection that crosses over the "origin & master" branch that you can see at the bottom of the list for other screenshots. Since the list is not in focus, it is impossible to tell if I only selected the two commits in "master", of if my selection also includes commits from the current branch.

The built-in themes do not suffer from this issue as they use different colors to highlight the selection and the current branch.

Application: All