Apparently, this used to be possible by editing the configuration through dconf-editor, but that is no longer the case.
Instead, what I'd suggest is using the plugin "Quick Open". This plugin comes already installed (at least in Zorin OS Core), all you have to do is enable it through the preferences menu:
This will create a new entry in the preferences menu to open files:
That contains a much larger list, which you can resize and scroll normally:
My personal recommendation is to get used to searching by typing the name of the file. This is available already on the default popup to open recent files, and what's not so obvious is that you can start typing the name of a recent file and it will find it.
For example, see in my previous screenshot you can see that there's a file called "config.json", but that doesn't show up in the recent files popup:
However, when I start typing that it filters the list of recent files and finds it right away:
I'd suggest getting used to work with the keyboard as much as possible. So, would press Alt+O to open that recent files popup, type the name of the file (partially, even), select it using the arrow keys and press Enter. Your hands don't leave the keyboard at all.
