The Gap Tool and Groups
[Guest author Ashley Mitchell was an Adobe staffer for over twenty years, mostly in the QE department, where as a senior tester he "tested almost every area of InDesign from InDesign 1.0 through CS5.5 (text, layout, UI, localization, you name it)." We're happy to welcome his contributions to the blog. —Anne-Marie]
Many people are familiar with how the Gap Tool works but a few special rules apply when groups are involved.
Below is a 5 x 5 grid of boxes within which the 9 red boxes having been grouped.
Under normal conditions the Gap Tool will look at every object on the page and find an appropriate gap. As far the Gap Tool is concerned, all the objects inside a group are treated as a single object and when you adjust a gap the entire group will resize or move as a single unit.
However, when the Gap Tool is positioned over a group it is only aware of those items within the group, and when you adjust a gap only those items within the group will be effected.
So next time you are using the Gap Tool and it seems as if it isn’t paying attention to all the objects that you think it should or you see objects resizing in an odd way, it could be that a group on the page is behind this seemingly odd or inconsistent behavior.