starmath: dispose SmEditController object correctly

Change-Id: I5d44ff6d514d2e40df23f6c419463b980f39d2c7
diff --git a/starmath/source/view.cxx b/starmath/source/view.cxx
index 4e4ad79..b6b1480 100644
--- a/starmath/source/view.cxx
+++ b/starmath/source/view.cxx
@@ -727,6 +727,7 @@ void SmCmdBoxWindow::dispose()
{
    aInitialFocusTimer.Stop();
    bExiting = true;
    aController.dispose();
    aEdit.disposeAndClear();
    SfxDockingWindow::dispose();
}