I have [custom] component that change its width  but not height  on resize. Cause is probably a bug in SWT Designer.  This code was auto generated and produce a problem 

GroupLayout gl_shell = new GroupLayout(shell);

        gl_shell.setHorizontalGroup(

            gl_shell.createParallelGroup(GroupLayout.LEADING)

                .add(composite, GroupLayout.DEFAULT_SIZE, 800, Short.MAX_VALUE)

        );

        gl_shell.setVerticalGroup(

            gl_shell.createParallelGroup(GroupLayout.LEADING)

                .add(composite)//problem here

        );

that looks like:

Untitled

changing code to :

 

gl_shell.setHorizontalGroup(

            gl_shell.createParallelGroup(GroupLayout.LEADING)

                .add(composite, GroupLayout.DEFAULT_SIZE, 800, Short.MAX_VALUE)

        );

        

        gl_shell.setVerticalGroup(

                gl_shell.createParallelGroup(GroupLayout.LEADING)

                    .add(composite, GroupLayout.DEFAULT_SIZE, 542, Short.MAX_VALUE)

            );

solve the problem.