Fix switching voices from the middle of a tuplet

src/notation/internal/notationnoteinput.cpp

@@ -454,6 +454,20 @@ void NotationNoteInput::setCurrentVoice(voice_idx_t voiceIndex)
     }
 
     mu::engraving::InputState& inputState = score()->inputState();
+
+    // TODO: Inserting notes to a new voice in the middle of a tuplet is not yet supported. In this case
+    // we'll move the input to the start of the tuplet...
+    if (const Segment* prevSeg = inputState.segment()) {
+        const ChordRest* prevCr = prevSeg->cr(inputState.track());
+        //! NOTE: if there's an existing ChordRest at the new voiceIndex, we don't need to move the cursor
+        if (prevCr && prevCr->topTuplet() && !prevSeg->cr(voiceIndex)) {
+            Segment* newSeg = score()->tick2segment(prevCr->topTuplet()->tick());
+            if (newSeg) {
+                inputState.setSegment(newSeg);
+            }
+        }
+    }
+
     inputState.setVoice(voiceIndex);
     notifyAboutStateChanged();
 }