What's your Xorg configuration?
(I don't work for LGP; Though during the beta phase, I did install X3 on a number of machine with different hardware configuration [in-order to test it] and never cam across your problem)
Oh, have you used to the LGP_Update utility to update to the latest version?
DEV: Intel S2600C0, 2xE52658V2, 32GB, 4x2TB + 2x3TB, GTX780, F21/x86_64, Dell U2711.
SRV: Intel S5520SC, 2xX5680, 36GB, 4x2TB, GTX550, F21/x86_64, Dell U2412..
BACK: Tyan Tempest i5400XT, 2xE5335, 8GB, 3x1.5TB, 9800GTX, F21/x86-64.
LAP: ASUS N56VJ, i7-3630QM, 16GB, 1TB, 635M, F21/x86_64.