Do not allow magic/combat stance unless magic/inventory window are accessible

apps/openmw/mwinput/inputmanagerimp.cpp

@@ -643,6 +643,10 @@ namespace MWInput
     {
         if (mWindows.isGuiMode()) return;
 
+        // Not allowed before the magic window is accessible
+        if (!mWindows.isAllowed(MWGui::GW_Magic))
+            return;
+
         MWMechanics::DrawState_ state = mPlayer.getDrawState();
         if (state == MWMechanics::DrawState_Weapon || state == MWMechanics::DrawState_Nothing)
             mPlayer.setDrawState(MWMechanics::DrawState_Spell);
@@ -654,6 +658,10 @@ namespace MWInput
     {
         if (mWindows.isGuiMode()) return;
 
+        // Not allowed before the inventory window is accessible
+        if (!mWindows.isAllowed(MWGui::GW_Inventory))
+            return;
+
         MWMechanics::DrawState_ state = mPlayer.getDrawState();
         if (state == MWMechanics::DrawState_Spell || state == MWMechanics::DrawState_Nothing)
             mPlayer.setDrawState(MWMechanics::DrawState_Weapon);