I can't tell what is triggering this, but it has happened several times that the toolbar in the schema browser is no longer displayed.
It does not matter which tab is displayed.
If I start another schema browser, the toolbar is displayed for this one.
When it disappears - is it missing from the moment that schema browser opens, or does something happen to make it disappear? Also, does adjusting the splitter between the LHS and RHS help?
Is the tables toolbar the only one that has disappeared?
So far, the toolbar has only disappeared for schema browsers that are already open. That means it is always present for newly opened ones.
I have never tried to adjust the splitter and unfortunately I have closed the schema browser from the screenshot in the meantime.
This morning I only checked the "Tables" and "Packages" tabs and there the toolbar was gone on both. (See the first two screenshots)
Next time it occurs, I'll try the splitter thing and see if all tabs are affected.