Hello, the latest SVN revision at the time of writing (945) doesn't show correctly the border of GBC ROMs.
I've checked it in the Windows build and in Linux (running through Wine 1.43). If in Linux and using the VBA-M GTK version the video is not working when the borders are activated, but the game is running (you can tell by the sound).
I've checked it works with VBA 1.7.2, both in Windows and Linux (using the GTK interface).
If required I can provide the ROM I was testing, or the patches needed to build VBA 1.7.2 with GCC4.1+.
Not a bug.
The 1.7.2 behavior was a buggy hack, forcing the SGB border on the GBC video output. If you want the borders on GBC titles then force an SGB mode.