diff --git a/aqt/tagedit.py b/aqt/tagedit.py
index 85c83cb9e..547e9055e 100644
--- a/aqt/tagedit.py
+++ b/aqt/tagedit.py
@@ -36,7 +36,28 @@ class TagEdit(QLineEdit):
         self.showCompleter()
 
     def keyPressEvent(self, evt):
+        if evt.key() in (Qt.Key_Up, Qt.Key_Down):
+            # show completer on arrow key up/down
+            if not self.completer.popup().isVisible():
+                self.showCompleter()
+            return
+        if (evt.key() == Qt.Key_Tab and evt.modifiers() & Qt.ControlModifier):
+            # select next completion
+            if not self.completer.popup().isVisible():
+                self.showCompleter()
+            index = self.completer.currentIndex()
+            self.completer.popup().setCurrentIndex(index)
+            cur_row = index.row()
+            if not self.completer.setCurrentRow(cur_row + 1):
+                self.completer.setCurrentRow(0)
+            return
         if evt.key() in (Qt.Key_Enter, Qt.Key_Return):
+            # apply first completion if no suggestion selected
+            selected_row = self.completer.popup().currentIndex().row()
+            if selected_row == -1:
+                self.completer.setCurrentRow(0)
+                index = self.completer.currentIndex()
+                self.completer.popup().setCurrentIndex(index)
             self.hideCompleter()
             QWidget.keyPressEvent(self, evt)
             return
@@ -70,12 +91,15 @@ class TagCompleter(QCompleter):
         self.cursor = None
 
     def splitPath(self, tags):
-        tags = tags.strip()
-        tags = re.sub("  +", " ", tags)
-        self.tags = self.edit.col.tags.split(tags)
+        stripped_tags = tags.strip()
+        stripped_tags = re.sub("  +", " ", stripped_tags)
+        self.tags = self.edit.col.tags.split(stripped_tags)
         self.tags.append("")
         p = self.edit.cursorPosition()
-        self.cursor = tags.count(" ", 0, p)
+        if tags.endswith("  "):
+            self.cursor = len(self.tags) - 1
+        else:
+            self.cursor = stripped_tags.count(" ", 0, p)
         return [self.tags[self.cursor]]
 
     def pathFromIndex(self, idx):
@@ -87,4 +111,4 @@ class TagCompleter(QCompleter):
             self.tags.remove("")
         except ValueError:
             pass
-        return " ".join(self.tags)
+        return " ".join(self.tags) + " "
\ No newline at end of file