Attempt to fix some crashes, but finding the actual underlying trigge…

…r is going to be difficult.

xLights/LayoutPanel.cpp

@@ -877,6 +877,7 @@ void LayoutPanel::OnPropertyGridChange(wxPropertyGridEvent& event) {
     }
     else {
         if (editing_models) {
+            xlights->AbortRender();
             if (selectedBaseObject != nullptr) {
                 Model* selectedModel = dynamic_cast<Model*>(selectedBaseObject);
                 //model property
@@ -946,6 +947,7 @@ void LayoutPanel::OnPropertyGridChanging(wxPropertyGridEvent& event) {
     xlights->AddTraceMessage("LayoutPanel::OnPropertyGridChanging  Property: " + name);
     if (selectedBaseObject != nullptr) {
         if( editing_models ) {
+            xlights->AbortRender();
             Model* selectedModel = dynamic_cast<Model*>(selectedBaseObject);
             if ("ModelName" == name) {
                 std::string safename = Model::SafeModelName(event.GetValue().GetString().ToStdString());

xLights/models/ModelGroup.cpp

@@ -864,7 +864,6 @@ bool ModelGroup::SubModelRenamed(const std::string &oldName, const std::string &
 }
 
 bool ModelGroup::CheckForChanges() const {
-
     unsigned long l = 0;
     for (const auto& it : models) {
         ModelGroup *grp = dynamic_cast<ModelGroup*>(it);
@@ -875,6 +874,13 @@ bool ModelGroup::CheckForChanges() const {
     }
 
     if (l != changeCount) {
+        if (!wxThread::IsMain()) {
+            //calling reset on any thread other than the main thread is bad.  In theory, any changes to the group/model
+            //would only be done on the main thread after an abortRender call so we shouldn't get here, but we are
+            //seeing stack traces in crash reports that show otherwise so likely some abortRender calls are missing.
+            return false;
+        }
+
         // this is ugly ... it is casting away the const-ness of this
         ModelGroup *group = (ModelGroup*)this;
         if (group != nullptr) group->Reset();