Fixing Rich Text Editor position for better cross-browser stability.

[ozayo]

If the admin enables the Rich Text Editor, it should remain in a fixed position.

The "floating" editor that appears upon text selection often causes compatibility issues across different browsers.
Check: #119

Please provide an option to pin the editor toolbar either to the top or bottom of the post area.

[mortondev]

I've tried to resolve the issue of the context menu popover being cut off by the edge of the dialog.

Is it still happening for you on more recent versions? I've not been able to reproduce it as you showed in the screenshot