RXP went up on increased volume the day it went ex dividend........

RXP went up on increased volume the day it went ex dividend..... weird.
Considering taking 1/2 a position at $0.835 and the second 1/2 at $0.905.
What is holding me back is that poor response to the recent shakeout bar and the test back contained a fair bit of volume but was also the day before it went ex dividend. I know a lot of people who sell before ex dividend and buy once it goes ex dividend hoping to gain extra which often works. However in this instance it failed and they may have been caught out thus resulting in yesterdays rise in price.