What am I doing wrong?

I have a layout that contains a header and body area. If I try to increase the size (vertical) of the header, then if I try to restore it back to the original size by sliding the line that delimits the area (not sure of the correct name) back to where it was originally, it refuses to do so and leaves white space around the graphics ... this layout uses coloured rectangles behind the fields.

The only way (that I could find) to recover from this was not to save the layout. I had this happen on another layout. I made the mistake of saving it and was not able to restore it to its original condition. (Perhaps I could have by copying it from a backup copy but I did not think of that at the time.)

In a case like this, I usually find that I've left an empty text block or white line or some other extraneous object near the bottom of the header. When you try to drag the part seperator over it, it stops at the bottom-most object in that part.

Selecting all objects on the layout usually helps identify the object that is preventing the resize. You can either delete or resize the object, or hold your option key down while you drag the seperator over it, leaving that object in the body while shrinking the header.

If there was an empty block would that not have prevented the bar being there in the first place?

But you are right ... I had done that before (on another layout) and I thought I had removed them all, but I must have missed some. I suspect they were there to close the very small gap between the header and body that seems impossible to remove.

Thanks