Allow multiple insertion of citation key with qualified citation lists

Fixes: #11618

src/frontends/qt/GuiCitation.cpp

@@ -368,6 +368,8 @@ void GuiCitation::updateFormatting(CitationStyle const & currentStyle)
 		availableLV->setToolTip(qt_("All references available for citing.\n"
 					    "To add the selected one, hit Add, press Enter or double-click.\n"
 					    "Hit Ctrl-Enter to add and close the dialog."));
+	// With qualified citation lists, it makes sense to add the same key multiple times
+	selectionManager->allowMultiSelection(currentStyle.hasQualifiedList);
 }
 
 

src/frontends/qt/GuiSelectionManager.cpp

@@ -55,7 +55,8 @@ GuiSelectionManager::GuiSelectionManager(QObject * parent,
 : QObject(parent), availableLV(avail), selectedLV(sel),
   addPB(add), deletePB(del), upPB(up), downPB(down),
   availableModel(amod), selectedModel(smod),
-  selectedHasFocus_(false), main_sel_col_(main_sel_col)
+  selectedHasFocus_(false), main_sel_col_(main_sel_col),
+  allow_multi_selection_(false)
 {
 	selectedLV->setModel(smod);
 	availableLV->setModel(amod);
@@ -144,7 +145,7 @@ void GuiSelectionManager::updateAddPB()
 		availableLV->selectionModel()->selectedIndexes();
 	addPB->setEnabled(arows > 0 &&
 		!availSels.isEmpty() &&
-		!isSelected(availSels.first()));
+		(allow_multi_selection_ || !isSelected(availSels.first())));
 }
 
 

src/frontends/qt/GuiSelectionManager.h

@@ -67,6 +67,8 @@ public:
 	/// Returns the selected index. Note that this will depend upon
 	/// selectedFocused().
 	QModelIndex getSelectedIndex(int const c = 0) const;
+	///
+	void allowMultiSelection(bool b) { allow_multi_selection_ = b; }
 
 Q_SIGNALS:
 	/// Emitted when the list of selected items has changed.
@@ -148,6 +150,8 @@ private:
 	bool selectedHasFocus_;
 	///
 	int main_sel_col_;
+	///
+	bool allow_multi_selection_;
 };
 
 } // namespace frontend