diff --git a/Source/Engine/Gramambular/Grid.h b/Source/Engine/Gramambular/Grid.h
index e13c8eab..d4103c99 100644
--- a/Source/Engine/Gramambular/Grid.h
+++ b/Source/Engine/Gramambular/Grid.h
@@ -47,7 +47,18 @@ namespace Formosa {
             size_t width() const;
             vector<NodeAnchor> nodesEndingAt(size_t inLocation);
             vector<NodeAnchor> nodesCrossingOrEndingAt(size_t inLocation);
+
+            // "Freeze" the node with the unigram that represents the selected canditate value.
+            // After this, the node that contains the unigram will always be evaluated to that
+            // unigram, while all other overlapping nodes will be reset to their initial state
+            // (that is, if any of those nodes were "frozen" or fixed, they will be unfrozen.)
             void fixNodeSelectedCandidate(size_t location, const string& value);
+
+            // Similar to fixNodeSelectedCandidate, but instead of "freezing" the node, only
+            // boost the unigram that represents the value with an overriding score. This
+            // has the same side effect as fixNodeSelectedCandidate, which is that all other
+            // overlapping nodes will be reset to their initial state.
+            void overrideNodeScoreForSelectedCandidate(size_t location, const string& value, float overridingScore);
             
             const string dumpDOT();
             
@@ -194,6 +205,24 @@ namespace Formosa {
                 }
             }
         }
+
+        inline void Grid::overrideNodeScoreForSelectedCandidate(size_t location, const string& value, float overridingScore)
+        {
+            vector<NodeAnchor> nodes = nodesCrossingOrEndingAt(location);
+            for (auto nodeAnchor : nodes) {
+                auto candidates = nodeAnchor.node->candidates();
+
+                // Reset the candidate-fixed state of every node at the location.
+                const_cast<Node*>(nodeAnchor.node)->resetCandidate();
+
+                for (size_t i = 0, c = candidates.size(); i < c; ++i) {
+                    if (candidates[i].value == value) {
+                        const_cast<Node*>(nodeAnchor.node)->selectFloatingCandidateAtIndex(i, overridingScore);
+                        break;
+                    }
+                }
+            }
+        }
         
         inline const string Grid::dumpDOT()
         {
diff --git a/Source/InputMethodController.mm b/Source/InputMethodController.mm
index dfc43e3d..9e48f829 100644
--- a/Source/InputMethodController.mm
+++ b/Source/InputMethodController.mm
@@ -150,6 +150,19 @@ public:
     }
 };
 
+static const double kEpsilon = 0.000001;
+
+static double FindHighestScore(const vector<NodeAnchor>& nodes, double epsilon) {
+    double highestScore = 0.0;
+    for (auto ni = nodes.begin(), ne = nodes.end(); ni != ne; ++ni) {
+        double score = ni->node->highestUnigramScore();
+        if (score > highestScore) {
+            highestScore = score;
+        }
+    }
+    return highestScore + epsilon;
+}
+
 @implementation McBopomofoInputMethodController
 - (void)dealloc
 {
@@ -665,32 +678,14 @@ public:
         [self popOverflowComposingTextAndWalk:client];
 
         // get user override model suggestion
-        string overrideCandidate =
+        string overrideValue =
             (_inputMode == kPlainBopomofoModeIdentifier) ? "" :
                 _uom->suggest(_walkedNodes, _builder->cursorIndex(), [[NSDate date] timeIntervalSince1970]);
-        if (!overrideCandidate.empty()) {
+        if (!overrideValue.empty()) {
             size_t cursorIndex = [self actualCandidateCursorIndex];
             vector<NodeAnchor> nodes = _builder->grid().nodesCrossingOrEndingAt(cursorIndex);
-
-            double highestScore = 0.0;
-            for (auto ni = nodes.begin(), ne = nodes.end(); ni != ne; ++ni) {
-                double score = ni->node->highestUnigramScore();
-                if (score > highestScore) {
-                    highestScore = score;
-                }
-            }
-            highestScore += 0.00001;
-
-            for (vector<NodeAnchor>::iterator ni = nodes.begin(), ne = nodes.end(); ni != ne; ++ni) {
-                const vector<KeyValuePair>& candidates = (*ni).node->candidates();
-                for (size_t i = 0, c = candidates.size(); i < c; ++i) {
-                    if (candidates[i].value == overrideCandidate) {
-                        // found our node
-                        const_cast<Node*>((*ni).node)->selectFloatingCandidateAtIndex(i, highestScore);
-                        break;
-                    }
-                }
-            }
+            double highestScore = FindHighestScore(nodes, kEpsilon);
+            _builder->grid().overrideNodeScoreForSelectedCandidate(cursorIndex, overrideValue, highestScore);
         }
 
         // then update the text