Display problems with Ubuntu vm on W10 host

[VBnovice]

My laptop runs on Windows 10 Home.
I installed the latest Ubuntu as a guest vm in the latest Virtualbox. Essentially that works fine. The mouse and keyboard work well. So does clipboard, etc.
One place where I have some problems is in the display and they are minor. I'll explain.

Using Firefox both in W10 and in Ubuntu,
1. some elements like the formatting bar is absent in Linux. See images.
On the left in the Ubuntu Firefox (no formatting bar), on the right W10 with formatting bar

2. scroll bar iis much narrower in Ubuntu than in W10

Are these discrepancies due to the OSs, different browser versions, or because of display in virtualbox? Can they be fixed?

[socratis]

Are these discrepancies due to the OSs, different browser versions, or because of display in virtualbox?

Yes, yes, no. The application rendering has nothing to do with VirtualBox. Especially when we're not talking about 2D or 3D acceleration.

Can they be fixed?

Not from within VirtualBox, that's for sure...

[mpack]

I'm seeing an increase in the people posting images in dithered GIF format. These are inferior in quality and much larger (because of all the high frequency "noise" in the image) than the conventional PNG. Is there some retro fashion trend I'm not aware of that's making people choose this obsolete 90's era palette based (8bit) format to code a 24bit or 32bit image?

[socratis]

VBnovice,
I deleted your duplicate message. Keep in mind that according to the forum rules, duplicate posts are not allowed. It's not good etiquette. I wouldn't want to see a duplicate post again from you...

[VBnovice]

I was not aware I had a duplicate post. If I did, it was not on purpose.

[socratis]

I was not aware I had a duplicate post.

Your original post was on 2018-08-13, 01:29 (my time).
The second post was on 2018-08-13, 19:28, 18 hours later. Same wording, different size attachments.

Still I don't believe that this is a VirtualBox issue at all...