Make scene editor transformation mode shortcuts work without having to click on the viewport.

I'm not sure if it's a bug, but at the moment to be able to switch transformation modes (by pressing W/E/R keys), you have to specifically click on the viewport section of the editor.
It gets in the way especially, when you did a quick change in the Entity tree, and would like to switch to rotation mode by pressing R (for example), rotate some entities in the viewport. The only way to enable rotation would be by pressing "Use rotation gizmo" on the top of viewport (because the shortcut won't work) or by clicking anywhere on the scene (that, however, modifies the current selection of entities).

Start by locating the scene editor's transformation-mode shortcut handling and how keyboard focus changes between the Entity tree and viewport. Reproduce the issue by editing the Entity tree, pressing W/E/R, and confirming the shortcut changes mode without altering the current entity selection.