Just today I bought CC2 Barbarossa to Berlin on GOG and was thrilled that I could still find a playable version of the game. Imagine my dissapointment when I discovered that the unit selection is terrible in this version of the game. Vehicle units close to eachother are very hard to select without zooming all the way in. It is virtually impossible to select squad sized infantry units in halftracks which rather ruins the game as not being able to deploy your infantry is pretty awfull.
As of right now the game is unplayable.

In those situations, you can always use the + (plus) and - (minus) keys on the keyboard to scroll-select through all your units. If you have troops embarked as passengers in a halftrack this process will select them.

It's not a bug, though.

Found on page 36 of the pdf manual...

Show vehicles - Shift-V

Units embarked on vehicles can sometimes be hard to make out. By
toggling vehicles off, you will be able to see any passengers riding on or
in vehicles quickly. This hotkey also toggles display of pillboxes and
bunkers.

Note: The key here is to combine the hotkeys in a way to achieve the
result that you want. With a little practice, this will become second
nature to you. For example, when you’re playing on a large and heavily
forested map, use Shift-T and Shift-C to quickly scan the map for your
units. When you’re playing at night, Shift-B might work best (the unit
bases tend to stand out due to their bright colors in the dark surrounding
of the night). Finally, the + and – keys are useful for moving through
your units one at a time. Quickly, you will find your most favored hotkey
combinations and will be able to get the information you want when you
need it.

DrowWarrior has it 100% right. If you have trouble picking out troops inside carriers, press shift-v to make vehicles invisble - that is exactly why shift-v exists. You can also use shift-c to change the visual scale of the units to make them easier to see and click on. These aren't "bugs" but merely typical of how old games used to be. The number of hotkeys aren't overwhelming and in the in-game menu there's even a hotkeys tab to conveniently pull them up on the screen! You just aren't used to doing things this way, but it isn't difficult and I promise you it soon becomes second nature.

I realize this is an old thread, but this 100% is a bug. My father plays CMBO religiously and is overly picky about any differences to the game as he remembers it. He currently has the GOG version and a version installed from the original CD-ROM then patched to 1.12 and using dgVoodoo2. The GOG version has the bug where units are almost impossible to select while in a vehicle and the original CD version does not. I assume this is caused by how the game draws its graphics and how GOG have made edits to restore fog and utilize directx, but I don't know much about graphical game development. However,....

This is a very annoying and potentially game breaking bug (if for instance you play exclusively with the mouse) that has not been patched out of the GOG version, apparently because people are spreading the myth that "[this is]... merely typical of how old games used to be".

i just Shift-V to turn off the vehicles (which turns off the halftracks ), then select the infantry.

You're wrong. I've been playing these games for 20yrs, on every Windows OS since XP, and on intel, nvidia and amd graphics. And I have both GOG and CD versions. And btw, GOG didn't come up with the fog fix, that was a github guy (nazgul, irrc), gog just tweaked it. And you don't need voodoo, I don't use it. In fact gog's additional graphics files are either unnecessary or generally hurts the game. I've written to them about this - several times - and got nowhere because they're too pig-headed/ignorant or don't care. Sounds to me like your father either has the settings slightly different between versions, or it's some weirdass voodoo or hardware bug. I've posted elsewhere (and in my game review (for CMAK, irrc) about how to get this game working depending on whether you're using nvidia, amd or intel. Either way, selecting troops inside vehicles is fiddly, always has been, and that is why the hotkey has always existed. You're welcome.