NAV display brightness?

[Dr. C]

New here and I have a few questions about my '04 X3. I enjoy reading the forum discusions--there seem to be a lot of knowledgable owners here. Owing to my middle-aged eyesight, I like the brightness on the NAV screen at its maximum. But it won't stay that way--I'll go into settings, crank it up to its brightest, exit the settings and off I go. All is well for the current trip. Next time I get in the car, it's back to a dimmer setting and I repeat the drill. Is there a way to lock the display settings, particularly the brightness? Thanks in advance for any solutions from the board.