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
int cmax = maxColumnWidths[i];
			int d = cmax - cmin;
			int extra = D != 0 ? (d * W) / D : 0;
			if (i < numColumns - 1) {
				widths[i] = cmin + extra;
				rem += widths[i];
			} else {
				widths[i] = tableWidth - fixedPart - rem;
			}
		}
		return widths;
	}
	Point computeSize(int childIndex, int width, int indent, int maxWidth, int maxHeight) {
		int widthArg = width - indent;
		SizeCache controlCache = cache.getCache(childIndex);
		if (!isWrap(controlCache.getControl()))
			widthArg = SWT.DEFAULT;
		Point size = controlCache.computeSize(widthArg, SWT.DEFAULT);
		if (maxWidth!=SWT.DEFAULT)
			size.x = Math.min(size.x, maxWidth);
		if (maxHeight!=SWT.DEFAULT)
			size.y = Math.min(size.y, maxHeight);
		size.x += indent;
		return size;
	}
	void placeControl(Control control, TableWrapData td, int x, int y,
			int[] rowHeights, int row) {
		int xloc = x + td.indent;
		int yloc = y;
		int height = td.compSize.y;