TODO:
- core has its own devtools context menu implementation on tabs, it needs to be overwritten: https://github.com/breach/breach_core/blob/c72d6b02ada72bad3d2e75b7df60bda6fe88f3af/lib/core_controls.js#L113
- devtools: add close button
- devtools: make it resizable
- devtools: either store information about the visibility in each tab and then auto hide/show it on tab change, or at least just hide it on tab change