>>126
あたしゃSWT使ったこともないがこうじゃないかね？

TabFolder tabFolder = new TabFolder(parent, SWT.NONE);
TabItem tabItem = new TabItem(tabFolder, SWT.NONE);
SashForm sash = new SashForm(tabFolder, SWT.HORIZONTAL);
tabItem.setControl(sash);
Composite comp1 = new Composite(sash, SWT.NONE);
Composite comp2 = new Composite(sash, SWT.NONE);
comp1.setLayout(new FillLayout());
comp2.setLayout(new FillLayout());