I want to use gnome dock only as a launching panel, I don't want it to show currently opened windows. That is it should be just bookmark bar for favorite applications. How do I do this?
Try these two extensions:
I had tried the latter for some time and it worked ok.
From 17.10 onwards ubuntu ships with a dock enabled by default, you can tweak a lot of it's settings with dconf-editor. First install the package:
sudo apt install dconf-editor
Now open it, then use the search icon on the titlebar to search for "dock" and click on the first result, now search again for "show-running" and turn off the switch in first result.
If you are using the default gnome session instead, you have to first install the dash-to-dock extension, then apply the procedure above (you can set the dock to be permanently hidden as it is by default too).