Then why should it even be allowed to change video modes? The need for that however can easily be avoided by shifting the console to use its own designated window, instead of using a text mode in the first place.
I'm not a fan of windowed designs, so I never implemented this in RDOS. Rather, RDOS uses different views / consoles that run in full-screen mode. Typically, an app has its own console, and will not compete with other apps in a windowed design. The keyboard has reserved short-cuts (CTRL + funktion key) to switch between consoles. So the shell typically runs in a console, and can even run in more than one console. When a new app it started, it can be detached, and then runs in a new console (in the shell, this is done by using the @ character before the command). That's also why different consoles can run in different video modes (at least in the BIOS version). So a tool to display an JPEG image might setup the most suitable resolution that matches the picture size.
The terminal app we have developed runs full screen in its own console. It sets a fixed resolution (typically 640x480 or 800x600), and runs using a widget class library. When it is deployed, a loader application also runs in its own console (in text mode), but is invisible since there is no keyboard that can be used to switch consoles. The kernel debugger also typically is always running, and it also runs in its own console and is invisible unless you know how to switch to it.
Could easily be done by shifting the console to use its own designated window, and then resizing it. However, you will have to not use a text mode in the first place.
I have no plans to develop a windowed GUI.
If I do, it will be another user app that runs special apps, or runs console apps by limiting their consoles.