This patch attempts to resolve the main part of issue 400.
Users working on small images or text near an important detail often wish they could hide the on-canvas text editor (temporarily or permanently). @schumaml suggested in this comment that a toggle could be added to the text options toolbox to let the user control the visibility of on-canvas text editor. An example of the toggle in action is shown here:
GIMP_-_Hide_On-Canvas_Text_Editor
The default setting is "on" for discoverability and to prevent issues with user's current workflows.