If you have a buy position, for example, on a company which announces a dividend, your account will be credited/debited prior to market open on the day the stock goes 'ex-dividend'. Here's a typical example:
StarHub announces a 15cent dividend
You currently hold 3000 units of StarHub
15cent x 3000 = $450
$450 will be credited to your CFD account.
Please note that the amount you are credited or debited will be subject to the relevant tax holding rates according to the region in which the share is listed.