no direct ModelessDialog instantiation left

Change-Id: If31cf3c02ab714f45ebbc0139e0e77102b5eb2ba
Reviewed-on: https://gerrit.libreoffice.org/73325
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

include/vcl/dialog.hxx

@@ -188,7 +188,7 @@ class VCL_DLLPUBLIC ModelessDialog : public Dialog
                     ModelessDialog (const ModelessDialog &) = delete;
                     ModelessDialog & operator= (const ModelessDialog &) = delete;
 
-public:
+protected:
     explicit        ModelessDialog( vcl::Window* pParent, const OUString& rID, const OUString& rUIXMLDescription, Dialog::InitFlag eFlag = Dialog::InitFlag::Default );
 };
 

vcl/README.lifecycle

@@ -308,11 +308,11 @@ ways and often both.
 	Window that has already been destroyed. This can easily
 	happen via this sort of pattern:
 
-	ModelessDialog *pDlg = VclPtr<ModelessDialog>(nullptr /* parent */);
+	ModalDialog *pDlg = VclPtr<ModalDialog>(nullptr /* parent */);
 	// by here the pDlg quite probably points to free'd memory...
 
 	It is necessary in these cases to ensure that the *pDlg is
-	a VclPtr<ModelessDialog> instead.
+	a VclPtr<ModalDialog> instead.
 
 ** It crashes with some invalid memory #2...
 

vcl/qa/cppunit/lifecycle.cxx

@@ -299,7 +299,6 @@ void LifecycleTest::testLeakage()
         aObjects.push_back(LeakTestObject::Create<VclVButtonBox>(xVBox));
     }
 
-    aObjects.push_back(LeakTestObject::Create<ModelessDialog>(xParent, "PrintProgressDialog", "vcl/ui/printprogressdialog.ui"));
     aObjects.push_back(LeakTestObject::Create<ModalDialog>(xParent, "PrintProgressDialog", "vcl/ui/printprogressdialog.ui"));
     xParent.clear();