On Drupal 7, Having installed the Wysiwig module into /opt/drupal/modules/ and TinyMCE into sites/all/libraries/ I have them more-or-less working.
The problem is as follows:
- Edit content => See the editor; everything is great
- Switch text format Full HTML => Filtered HTML and vice versa => No editor at all
- Disable rich text => see the editor (no bar) as it should be
- Enable rich text => see the TinyMCE editor with the correct bar as it should be.
In other words, there is a glitch when switching text formats, requiring toggling rich text editing off and back on. There are no javascript errors or anything else that indicates, drupal knows something went wrong.