Width of sidebar while using Navigator

I recently upgraded to LO (x64) and now the sidebar (when using Navigator) is wider than before, obscuring 1/3 of the Writer window. When I switch to Styles, I can make the sidebar narrower, but as soon as I switch back to Navigator view, it pops back to the large width. The double arrow cursor that normally allows changing width can make the sidebar wider (to almost half the screen!) but never narrower than 1/3. Prior to the upgrade, I kept the sidebar at approximately 1/4 of the screen area.

ETA: This anomaly occurs only while using the Navigator available as an icon in the Styles sidebar called up by drop-down menu [Styles/Manage Styles] or key combination [F]+[11], but not in the Navigator available when clicking on the Navigator icon in the Standard tool bar, using drop-down menu [View/Navigator], or key combination [F}+[5}. Apparently, it is not possible to get JUST styles in the sidebar (i.e., without the associated Navigator icon that, when clicked makes the sidebar really wide).

Am I missing something?
Thanks in advance.