While on the screen you're showing, press the Alt key > press the V key > click Toolbars > click Menu Bar. Do the same steps to enable the Composition Bar. Then the Menu Bar and Composition Bars will always be visible. If you don't want the Menu bar ...
Can't reproduce that, @nunorr. As support requests aren't allowed here, please post your question with full details at https://support.mozilla.org/en-US/questions/new/thunderbird/form.
