Improve usage experience
Started from issue #237 (closed), this merge request implements several improvements to various editors.
Most of them are purely visual and provide tool tips that should help understand better what might be going on when clicking on one button or another.
Other improvements can be done in that regard and will happen during further development.
Relevant issue(s) fixed
Fixes #237 (closed)
Fixes #235 (closed)
Fixes #270 (closed)