WinXP screen resolution changed

[_AZ_]

Hello,
i run 2.6.32-220.7.1.el6.x86_64 #1 SMP (RHEL 6.2) on AMD Phenom(tm) II X4 830 Processor as a hostr and wp with SP3 as a guest.
VBox is VirtualBox-4.1-4.1.14_77440_rhel6-1.x86_64 with latest extensions and GA.
i recently switched guest from running in full screen mode into seamless which worked ok. but after i switched it back into full screen mode , the guest's screen resolution decreased from 1400x900 to 1400x801.
how do i restore the original resolution in guest?
TY
AZ

[_AZ_]

ekhhh "Host-G" did the trick.