[TD]prevent running threads on object delete

src/Mod/TechDraw/App/DrawViewDetail.cpp

@@ -109,6 +109,11 @@ DrawViewDetail::DrawViewDetail() :
 
 DrawViewDetail::~DrawViewDetail()
 {
+    //don't delete this object while it still has dependent tasks running
+    if (m_detailFuture.isRunning()) {
+        Base::Console().Message("%s is waiting for detail cut to finish\n", getNameInDocument());
+        m_detailFuture.waitForFinished();
+    }
 }
 
 short DrawViewDetail::mustExecute() const

src/Mod/TechDraw/App/DrawViewPart.cpp

@@ -155,6 +155,15 @@ DrawViewPart::DrawViewPart(void) :
 
 DrawViewPart::~DrawViewPart()
 {
+    //don't delete this object while it still has dependent threads running
+    if (m_hlrFuture.isRunning()) {
+        Base::Console().Message("%s is waiting for HLR to finish\n", getNameInDocument());
+        m_hlrFuture.waitForFinished();
+    }
+    if (m_faceFuture.isRunning()) {
+        Base::Console().Message("%S is waiting for face finding to finish\n", getNameInDocument());
+        m_faceFuture.waitForFinished();
+    }
     removeAllReferencesFromGeom();
     delete geometryObject;
 }

src/Mod/TechDraw/App/DrawViewSection.cpp

@@ -149,6 +149,11 @@ DrawViewSection::DrawViewSection()  :
 
 DrawViewSection::~DrawViewSection()
 {
+    //don't destroy this object while it has dependent threads running
+    if (m_cutFuture.isRunning()) {
+        Base::Console().Message("%s is waiting for tasks to complete\n", getNameInDocument());
+        m_cutFuture.waitForFinished();
+    }
 }
 
 short DrawViewSection::mustExecute() const