Apply open document shortcuts to the tree that has focus (#945)

* Better handling of Enter/Return on GUI trees, resolves #913
* Update test
* Generalise open selected handle functions
* Improve test coverage
* Update docstring

novelwriter/gui/outline.py

@@ -34,6 +34,7 @@ from PyQt5.QtWidgets import (
 )
 
 from novelwriter.enum import nwItemLayout, nwItemType, nwOutline
+from novelwriter.common import checkInt
 from novelwriter.constants import trConst, nwKeyWords, nwLabels
 
 logger = logging.getLogger(__name__)
@@ -196,6 +197,19 @@ class GuiOutline(QTreeWidget):
         self._firstView = True
         return
 
+    def getSelectedHandle(self):
+        """Get the currently selected handle. If multiple items are
+        selected, return the first.
+        """
+        selItem = self.selectedItems()
+        tHandle = None
+        tLine = 0
+        if selItem:
+            tHandle = selItem[0].data(self._colIdx[nwOutline.TITLE], Qt.UserRole)
+            tLine = checkInt(selItem[0].text(self._colIdx[nwOutline.LINE]), 1) - 1
+
+        return tHandle, tLine
+
     ##
     #  Slots
     ##
@@ -206,15 +220,8 @@ class GuiOutline(QTreeWidget):
         clicked, and send it to the main gui class for opening in the
         document editor.
         """
-        tHandle = tItem.data(self._colIdx[nwOutline.TITLE], Qt.UserRole)
-        try:
-            tLine = int(tItem.text(self._colIdx[nwOutline.LINE]))
-        except Exception:
-            tLine = 1
-
-        logger.verbose("User selected entry with handle '%s' on line %s", tHandle, tLine)
+        tHandle, tLine = self.getSelectedHandle()
         self.theParent.openDocument(tHandle, tLine=tLine-1, doScroll=True)
-
         return
 
     @pyqtSlot()