+ fixes #0001447: Crash when opening task dialog for orthographic projection while another task dialog is open

src/Gui/Control.cpp

@@ -24,6 +24,7 @@
 #include "PreCompiled.h"
 
 #ifndef _PreComp_
+# include <QDebug>
 # include <QDockWidget>
 # include <QPointer>
 #endif
@@ -93,8 +94,18 @@ void ControlSingleton::showModelView()
 
 void ControlSingleton::showDialog(Gui::TaskView::TaskDialog *dlg)
 {
-    // only one dialog at a time
-    assert(!ActiveDialog || ActiveDialog==dlg);
+    // only one dialog at a time, print a warning instead of raising an assert
+    if (ActiveDialog && ActiveDialog != dlg) {
+        if (dlg) {
+            qWarning() << "ControlSingleton::showDialog: Can't show "
+                       << dlg->metaObject()->className()
+                       << " since there is already an active task dialog";
+        }
+        else {
+            qWarning() << "ControlSingleton::showDialog: Task dialog is null";
+        }
+        return;
+    }
     Gui::DockWnd::CombiView* pcCombiView = qobject_cast<Gui::DockWnd::CombiView*>
         (Gui::DockWindowManager::instance()->getDockWindow("Combo View"));
     // should return the pointer to combo view

src/Mod/Drawing/Gui/Command.cpp

@@ -298,7 +298,7 @@ void CmdDrawingNewView::activated(int iMsg)
 // Drawing_OrthoView
 //===========================================================================
 
-DEF_STD_CMD(CmdDrawingOrthoViews);
+DEF_STD_CMD_A(CmdDrawingOrthoViews);
 
 CmdDrawingOrthoViews::CmdDrawingOrthoViews()
   : Command("Drawing_OrthoViews")
@@ -331,6 +331,13 @@ void CmdDrawingOrthoViews::activated(int iMsg)
     Gui::Control().showDialog(new TaskDlgOrthoViews());
 }
 
+bool CmdDrawingOrthoViews::isActive(void)
+{
+    if (Gui::Control().activeDialog())
+        return false;
+    return true;
+}
+
 
 //===========================================================================
 // Drawing_OpenBrowserView