It could be that the Desktop Manager provided by the Chromebook installation is just not capable. I run a 5 year old Acer C720 but there I replaced ChromeOS with a regular linux installation. The other bit about the C720 is the cut-down 32-bit Intel Atom processer. 32 bit more than adequate for the limited resources but can be limiting. You need to know what you are using. I will assume a modern Chromebook is 64 bit but I do not know.
FWIW 3 alternatives.
1. Alt-click and drag
2. Dialogue menu move option
3. Modified scrolling script-fu plugin.
This is demo and that is all it is, a demo, using my regular kubuntu laptop.
https://youtu.be/JT6rBlRCDdk duration 1 minute and a bit.
I will attach the 64 bit script-fu plugin. Unzip put in your Gimp 2.10 profile. Might / might-not work. I have a 32 bit version somewhere in my archive if needed.