fix ilistbox dispose.

Change-Id: Icc5b6e924dfeec7a7da4f654d79b17fe91ce1418
diff --git a/vcl/source/control/combobox.cxx b/vcl/source/control/combobox.cxx
index 441b3b5..2c78507 100644
--- a/vcl/source/control/combobox.cxx
+++ b/vcl/source/control/combobox.cxx
@@ -74,7 +74,11 @@ ComboBox::~ComboBox()
void ComboBox::dispose()
{
    mpSubEdit.disposeAndClear();
    mpImplLB.disposeAndClear();

    VclPtr< ImplListBox > pImplLB = mpImplLB;
    mpImplLB.clear();
    pImplLB.disposeAndClear();

    mpFloatWin.disposeAndClear();
    mpBtn.disposeAndClear();
    Edit::dispose();
diff --git a/vcl/source/control/ilstbox.cxx b/vcl/source/control/ilstbox.cxx
index e05746e..dc09182 100644
--- a/vcl/source/control/ilstbox.cxx
+++ b/vcl/source/control/ilstbox.cxx
@@ -2174,10 +2174,9 @@ ImplListBox::~ImplListBox()

void ImplListBox::dispose()
{
    mpHScrollBar.clear();
    mpVScrollBar.clear();
    mpScrollBarBox.clear();
    maLBWindow.clear();
    mpHScrollBar.disposeAndClear();
    mpVScrollBar.disposeAndClear();
    mpScrollBarBox.disposeAndClear();
    maLBWindow.disposeAndClear();
    Control::dispose();
}