At startup, dolphin shows blank spaces (empty panels) at bottom and right. A workaround is to enable the console panel, to resize it and disable it. Then dolphin refresh to the expected layout. This issue appeared just after an upgrade on Fedora to dolphin-17.12.2-2.fc27.x86_64
same workaround with metadata panel.
Can you attach a screenshot showing the empty panels?
*** This bug has been marked as a duplicate of bug 395881 ***