For information about Flot library go here. Works also with Time series data and supports Date formatting in the same way as Flot itself. You can fully define content of tip (with values precision) ...

This extension allows you to customize your folders in your workspace settings, by setting a color, badge (text or emoji) and tooltip. This is visible in the Explorer view and the tabs. Set Color Set ...

The cause for this appears to be a conflict between windows that want to stay on top. Tooltips always want to be on the top. But if like most of us do, you have the Taskbar set to be kept on top of ...