0.9.9
The user interface is losing its coherence due to the prevelence of colored icons, many of which are introducing a lot of inconsistency into the color scheme, so I am removing some unnexessary icons and reducing color in some places. However, during this phase I did discover that using object thumbnails and tool icons in the main menu looks awesome.
I have a better idea now of how and when I want to use color. As a general rule, I want color to be associated with 3D objects in the map. The scene browser is now using a yellow group / folder icon, and the topmost icon is using a lot of primary colors, which gives it a strong Lego-ish feel, and the objects that appear in the scene browser are using icons that closely match the object thumbnail in the drop-down object selector. Entities in the 3D scene are using the same colored icon, so it is easier to recognize which type of object is which. Monochrome outline icons are still used in the proporties editor, which feels right to me.
I experimented with displaying tools as a column of buttons in the left sidebar, but the initial results didn't look good. I may revisit this again, but for now the left sidebar is removed, since its purpose doesn't really justify its presence.