I figured out how shrink the gap.
There is a divisor to the left of the "parent" column title. I grabbed that and dragged to the left and it shrunk the gap.
I would like to know though if there is a way to restore preferences to the default.
As I said ctrl+alt+shift doesn't work.
This should also work:
Also you can move panels around by clicking on the tabs with the panel's name, holding down the mouse button and letting it go once you've found the highlight that correctly indicates where you want to move the panel. You can also undock the panels by right clicking and pressing Undock Panel. You can then move the panel around and drop it wherever the highlight indicates. Then adjust the size of the panels, by hovering over the edges until the double arrow cursor appears. This way you can completely customize your workspace. I work with two monitors so I do this all the time depending on what I'm doing in After Effects and what panels I need.
Myllenium, thxs for the tip but I have no idea how to follow the instructions in the link.