Re #28047 Fix crash when remove function and closing interface

docs/source/release/v4.3.0/mantidplot.rst

@@ -12,5 +12,6 @@ Bugfixes
 ########
 - The Show Instruments right click menu option is now disabled for workspaces that have had their spectrum axis converted to another axis using :ref:`ConvertSpectrumAxis <algm-ConvertSpectrumAxis>`.  Once this axis has been converetd the workspace loses it's link between the data values and the detectors they were recorded on so we cannot display it in the instrument view.
 - Fixed an issue with Workspace History where unrolling consecutive workflow algorithms would result in only one of the algorithms being unrolled.
+- Fixed an issue where mantid crashed if you cleared the functions in the multi-dataset fitting interface
 
 :ref:`Release 4.3.0 <v4.3.0>`
\ No newline at end of file

qt/widgets/common/src/FitOptionsBrowser.cpp

@@ -307,7 +307,9 @@ void FitOptionsBrowser::createSequentialFitProperties() {
   // Create LogValue property
   m_plotParameter = m_enumManager->addProperty("Plot parameter");
   {
-    m_propertyNameMap["PlotParameter"] = m_plotParameter;
+    addProperty("PlotParameter", m_plotParameter,
+                &FitOptionsBrowser::getStringEnumProperty,
+                &FitOptionsBrowser::setStringEnumProperty);
     m_sequentialProperties << m_plotParameter;
   }
 }

qt/widgets/common/src/FunctionModel.cpp

@@ -184,9 +184,11 @@ void FunctionModel::setParameterTie(const QString &parName, QString tie) {
 
 QStringList FunctionModel::getParameterNames() const {
   QStringList names;
-  const auto paramNames = getCurrentFunction()->getParameterNames();
-  for (auto const name : paramNames) {
-    names << QString::fromStdString(name);
+  if (hasFunction()) {
+    const auto paramNames = getCurrentFunction()->getParameterNames();
+    for (auto const name : paramNames) {
+      names << QString::fromStdString(name);
+    }
   }
   return names;
 }
@@ -398,7 +400,7 @@ void FunctionModel::setGlobalParameters(const QStringList &globals) {
 
 QStringList FunctionModel::getLocalParameters() const {
   QStringList locals;
-  for (auto const name : getParameterNames()) {
+  for (auto const &name : getParameterNames()) {
     if (!m_globalParameterNames.contains(name))
       locals << name;
   }