After an upgrade to Leap 42.3 (from 42.2), the left sidebar navigation panel in Konqueror is gone.
A search on the forum led me to https://forums.opensuse.org/showthread.php/521771-Konqueror-sidebar which indicates that that functionality has been dropped. 
This means that Konqueror is no longer productive for me.
One thing I used quite often in Konqueror was itâs context-sensitive âPreview in embedded viewerâ option. Turning on Preview for an entire directory is, to me, both silly from a performance perspective and virtually useless since the previews on text files, for example, are too small and limited.
So, the question is, how can I get similar âPreview in embedded viewerâ functionality in Dolphin? Is it possible?
If you enable tooltips (or turn on the information panel, F11), when you hover over a file dolphin will show a preview.
Dolphin preferences > General > Visualizations tab let you enable the file formats and maximum size you want to preview.
Additional preview extensions can be installed from Yast, search for thumbnail and see which ones you want. Theyâre usually named kde-thumb* or similar.
I did not find a âVisualizationsâ tab in Settings > Configure Dolphin > General, but there is a âPreviewsâ tab. 
Iâm sure thatâs what you meant and just mention it so others donât get confused.
I must say that Information Panel is quite useful, and I actually like it better than Konquerorâs two-step preview process.
Upon pressing F11, it appeared on the right-hand side of the directory content pane. I re-docked it over on the left side navigation panel along with Places and Folders. Nice.
Thank you very much.