[FEM] refactor GeometryElementsSelection, introduce parameter to modify help text for several task panels using GeometryElementsSelection.

src/Mod/Fem/femguiutils/selection_widgets.py

@@ -231,7 +231,7 @@ class SmallListView(QtGui.QListView):
 
 class GeometryElementsSelection(QtGui.QWidget):
 
-    def __init__(self, ref, eltypes=[], multigeom=True):
+    def __init__(self, ref, eltypes=[], multigeom, showHintEmptyList):
         super(GeometryElementsSelection, self).__init__()
         # init ui stuff
         FreeCADGui.Selection.clearSelection()
@@ -240,6 +240,7 @@ class GeometryElementsSelection(QtGui.QWidget):
         self.obj_notvisible = []
         self.initElemTypes(eltypes)
         self.allow_multiple_geom_types = multigeom
+        self.showHintEmptyList = showHintEmptyList
         # print(self.allow_multiple_geom_types)
         self.initUI()
         # set references and fill the list widget
@@ -276,11 +277,20 @@ class GeometryElementsSelection(QtGui.QWidget):
         # label
         self._helpTextLbl = QtGui.QLabel()
         self._helpTextLbl.setWordWrap(True)
-        self._helpTextLbl.setText(self.tr(
+        helpTextPart1 = self.tr('Click on "Add" and select geometric elements to add them to the list.')
-            'Click on "Add" and select geometric elements to add them to the list. '
+        helpTextPart2 = self.tr("The following geometry elements are allowed to select: ") + self.sel_elem_text
-            "If no geometry is added to the list, all remaining ones are used. "
+        helpTextPart3 = self.tr("If no geometry is added to the list, all remaining ones are used.")
-            "The following geometry elements are allowed to select: "
+        if self.showHintEmptyList is True:
-        ) + self.sel_elem_text)
+            self._helpTextLbl.setText(
+                helpTextPart1 + "\n" +
+                helpTextPart2 + "\n" +
+                helpTextPart3
+            )
+        else:
+            self._helpTextLbl.setText(
+                helpTextPart1 + "\n" +
+                helpTextPart2
+            )
         # list
         self.list_References = QtGui.QListWidget()
         # radiobutton down the list

src/Mod/Fem/femtaskpanels/task_constraint_sectionprint.py

@@ -55,7 +55,9 @@ class _TaskPanel:
         # geometry selection widget
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Face"]
+            ["Face"],
+            False,
+            False
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_constraint_tie.py

@@ -61,7 +61,9 @@ class _TaskPanel:
         # geometry selection widget
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Face"]
+            ["Face"],
+            False,
+            False
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_element_fluid1D.py

@@ -232,7 +232,10 @@ class _TaskPanel:
 
         # geometry selection widget
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
-            obj.References, ["Edge"]
+            obj.References,
+            ["Edge"],
+            False,
+            True
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_element_geometry1D.py

@@ -91,7 +91,9 @@ class _TaskPanel:
         # geometry selection widget
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Edge"]
+            ["Edge"],
+            False,
+            True
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_element_geometry2D.py

@@ -60,7 +60,9 @@ class _TaskPanel:
         # geometry selection widget
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Face"]
+            ["Face"],
+            False,
+            True
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_element_rotation1D.py

@@ -61,7 +61,9 @@ class _TaskPanel:
         # geometry selection widget
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Edge"]
+            ["Edge"],
+            False,
+            True
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_material_common.py

@@ -192,7 +192,8 @@ class _TaskPanel:
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
             ["Solid", "Face", "Edge"],
-            False
+            False,
+            True
         )  # start with Solid in list!
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_mesh_boundarylayer.py

@@ -72,7 +72,9 @@ class _TaskPanel:
         # start with Solid in list!
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Solid", "Face", "Edge", "Vertex"]
+            ["Solid", "Face", "Edge", "Vertex"],
+            True,
+            False
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_mesh_group.py

@@ -66,7 +66,9 @@ class _TaskPanel:
         # start with Solid in list!
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Solid", "Face", "Edge", "Vertex"]
+            ["Solid", "Face", "Edge", "Vertex"],
+            True,
+            False
         )
 
         # form made from param and selection widget

src/Mod/Fem/femtaskpanels/task_mesh_region.py

@@ -61,7 +61,9 @@ class _TaskPanel:
         # start with Solid in list!
         self.selectionWidget = selection_widgets.GeometryElementsSelection(
             obj.References,
-            ["Solid", "Face", "Edge", "Vertex"]
+            ["Solid", "Face", "Edge", "Vertex"],
+            True,
+            False
         )
 
         # form made from param and selection widget