GroupKeepTogether applies to a group and has similar to the KeepTogether meaning, but for the whole group. It indicates whether the rendering engine should try to render the whole group on a single page, the group header plus the first detail on a single page, or leave the group flow as it is. If GroupKeepTogether is set to FirstDetail -- the group header and at least one detail in this group should be on the same page; if set to All -- the whole group should be on a single page. The following rule applies: the rendering engine will try to render the group as specified, but if there is not enough space on the current page, the group is moved to the next page and it continues as long as it needs.
public enum GroupKeepTogether
The rendering engine should try to keep the whole group on the same page. This value has higher priority compared with the PageBreak property of the contained report sections.
The rendering engine should try to keep the group header and at least 1 detail on the same page.
The rendering engine will leave the group flow as it is.