Crystal Report displaying Group Header multiple times

Hi I am using Crystal Reports 10 to generate my reports. In one of the reports 开发者_JAVA百科I see that a group header is getting repeated 2 times in the output document while in the design tab I can that it is present only one time. I am having my query as a "Union All" of 2 data sets.

Please advise what could be the cause. Thanks.

Your grouping condition just generates two different groups and some detail suppression condition kills details for one of these groups?

Create "debug" detail section without any conditions and show there some non-empty field from leftmost table from your data tree (and optionally something from other tables) - usually this helps to debug such problems out. (I usually make such debug fields red to rememeber hide that section before sending report to customer :)) Check too that "convert null values" options in report options are set appropriately.