Hello there,
The Mac versions of Spiderweb games can behave slightly different, if you are used to the Windows versions. Most notably will be severely increased stability.
Jeff Vogel used to compile his Mac versions first, this may explain why, sadly, enemy HP numbers aren't shown in the Mac version.
Damage calculations are also slightly different on Mac.
The "white background" issue, is something consistently haunting all Mac Geneforge 4 versions.
(Image below, Boiling Caverns, demo version, OSX 10.5)
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You may also have noticed that the "dirt wall" in the early Geneforges looks different in the Mac versions.
(Image below, Crumbling Docks, demo version, OSX 10.5)
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But the cursor issue is something I have yet to experience.
I have bootable partitions with OSX's 10.4 to 10.11, but I have to admit I prefer to boot up on Mountain Lion (10.8) when I can,
so that's the only OSX on which I have played Spiderweb games for a considerable amount of time (grave understatement here).
Since Mountain Lion is one of the "better" OSX's and, arguably, together with Tiger (10.4) *the best *,
I cannot be a veritable stability-test account and I have yet to experience a crash or any such unforgivable design feature.
However, when you activate Mission Control, the cursor should change back to the standard Apple cursor, perhaps that's what's happening?
Try downloading the demo version on another Mac, preferably running another OS and see if the cursor still behaves oddly.
EDIT: sorry I can't add any image in this reply.