I am using Toast Titanium 9 and the version of Disc Cover 2 RE that comes with it on a Mac — previously on a PPC eMac with OS 10.4.11 and with a built-in Apple CRT display, then (briefly) on a PPC Mac mini with OS 10.4.11 but with a Samsung SyncMaster 172V display, now on an Intel one with OS 10.8.3 and the same Samsung display.
On the eMac with its CRT display, Disc Cover worked very well. With both my more recent computers, using the Samsung SyncMaster display, the circles representing the outer and inner limits of the design when designing a CD label are virtually invisible, making the placing of text and images almost impossible.
My screen contrast is set to maximum and so is the resolution. Changing the resolution has no effect on the visibility of the Disc Cover circles. But in a drawing program the thinnest hair lines are sharply visible and deep black, so this Disc Cover phenomenon seems not directly to be the fault of the Samsung display. If anyone has any suggestions, I should be very grateful.