We should try to make the users job easier when they create and customize a 
gridbaglayout.  Currently it seems that every component type gets the same 
initial set of GridBagConstraints values (as seen in the gridbaglayout 
customizer).  This is not always a good default set for all component types. In 
particular the "fill" value should not be "none" by default for the containers 
JPanel and JTable (it should probably be "both" by default) -- that is probably 
what the user will want, and "none" is almost surely not what they will want.

The current default value of "fill=none" can cause users debugging problems 
where they run their new window and do not see their JPanel or JTable component 
at all, or it is very small, and it can be hard to figure out what is wrong.
The user will wonder "where is my container?" and they may check minimum and 
preferred sizes, etc. when the problem is really the default "fill" value we 
gave it.

This is a particular example, but a fairly important one I believe, as I have 
seen it cause problems and waste time. There may be other cases too where 
different defaults would be good, and I will try to watch for those, and if I 
find any in the future I will add them to this enhancement request.