allow wxDialog::ShowModal() after Show() (see #1416, #4658, #4664)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@54328 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/dialog.cpp

@@ -99,7 +99,6 @@ void wxDialog::SetModal( bool WXUNUSED(flag) )
 int wxDialog::ShowModal()
 {
     wxASSERT_MSG( !IsModal(), "ShowModal() can't be called twice" );
-    wxASSERT_MSG( !IsShown(), "ShowModal() can't be called after Show()" );
 
     // release the mouse if it's currently captured as the window having it
     // will be disabled when this dialog is shown -- but will still keep the

src/msw/dialog.cpp

@@ -283,8 +283,7 @@ void wxDialog::Raise()
 // show dialog modally
 int wxDialog::ShowModal()
 {
-    wxASSERT_MSG(!IsShown(),
-                 _T("ShowModal() can't be called for an already shown dialog"));
+    wxASSERT_MSG( !IsModal(), _T("ShowModal() can't be called twice") );
 
     m_endModalCalled = false;
 

src/osx/carbon/dialog.cpp

@@ -169,7 +169,10 @@ int wxDialog::ShowModal()
     if ( !m_isModalStyle )
         SetModal(true);
 
-    Show(true);
+    if ( IsShown() )
+        DoShowModal();
+    else
+        Show(true);
 
     return GetReturnCode();
 }