Bug 89824 [Forms] Position of Go button in Help Search view changes
If you expand and contract the Default Scope area the position of the Go button will shift (and the combo will shrink and grow). I will attach two screencaps - note the space to the right of the Go button.
bundles/org.eclipse.ui.forms/src/org/eclipse/ui/forms/widgets/TableWrapLayout.java
* Updates this row span's height with the given one if it is within
		 * this span.
		 */
		public void update(int currentRow, int rowHeight) {
			TableWrapData td = (TableWrapData) child.getLayoutData();
			
			if (currentRow >= row && currentRow < row + td.rowspan) {
				totalHeight += rowHeight;
				if (currentRow > row)
					totalHeight += verticalSpacing;
			}
		}
		public int getRequiredHeightIncrease() {
			if (totalHeight < height)
				return height - totalHeight;
			return 0;
		}
	}
	/**
	 * Implements ILayoutExtension. Should not be called directly.
	 * 
	 * @see ILayoutExtension
	 */
	public int computeMinimumWidth(Composite parent, boolean changed) {
		Control[] children = parent.getChildren();
		if (changed) {
			cache.flush();
		}
		cache.setControls(children);
		changed = true;