diff --git a/editor/src/EditorState.h b/editor/src/EditorState.h
index 710aca6..7dfd15b 100644
--- a/editor/src/EditorState.h
+++ b/editor/src/EditorState.h
@@ -208,6 +208,7 @@ struct EditorState {
     double            symbolsLastChange = 0.0;
     bool              completionPending = false;
     bool              completionVisible = false;
+    bool              completionDismissed = false;
     int               completionSelected = 0;
     double            completionLastChange = 0.0;
     bool              lspChangePending = false;
@@ -601,4 +602,3 @@ struct NullLSPTransport : public LSPTransport {
     bool isOpen() const override { return false; }
     void close() override {}
 };
-
diff --git a/editor/src/panels/EditorPanel.h b/editor/src/panels/EditorPanel.h
index cf2660c..4032bc7 100644
--- a/editor/src/panels/EditorPanel.h
+++ b/editor/src/panels/EditorPanel.h
@@ -324,6 +324,7 @@ static void renderEditorPanel(EditorState& state) {
                                 state.completionPending = true;
                                 state.completionLastChange = ImGui::GetTime();
                                 state.completionVisible = false;
+                                state.completionDismissed = false;
                                 state.completionSelected = 0;
                                 if (state.lsp) state.lsp->clearCompletionItems();
                                 if (state.lsp && state.active() && state.active()->path.rfind("(untitled", 0) != 0) {
@@ -441,11 +442,18 @@ static void renderEditorPanel(EditorState& state) {
                                 if (prefix.empty() || key.rfind(prefix, 0) == 0) filtered.push_back(item);
                             }
 
-                            state.completionVisible = !filtered.empty();
+                            if (filtered.empty()) {
+                                state.completionVisible = false;
+                                state.completionDismissed = false;
+                            } else if (!state.completionDismissed) {
+                                state.completionVisible = true;
+                            }
                             if (state.completionVisible) {
                                 ImGui::SetCursorScreenPos(ImVec2(ImGui::GetWindowPos().x + 20.0f,
                                                                  ImGui::GetWindowPos().y + 60.0f));
                                 ImGui::BeginChild("##completionPopup", ImVec2(300, 150), true);
+                                bool popupHovered =
+                                    ImGui::IsWindowHovered(ImGuiHoveredFlags_AllowWhenBlockedByPopup);
                                 int maxIndex = std::max(0, (int)filtered.size() - 1);
                                 if (ImGui::IsKeyPressed(ImGuiKey_DownArrow)) {
                                     state.completionSelected = std::min(state.completionSelected + 1, maxIndex);
@@ -459,6 +467,7 @@ static void renderEditorPanel(EditorState& state) {
                                 if (dismiss) {
                                     state.lsp->clearCompletionItems();
                                     state.completionVisible = false;
+                                    state.completionDismissed = true;
                                 }
 
                                 auto deriveLibrary = [](const std::string& name) {
@@ -503,8 +512,13 @@ static void renderEditorPanel(EditorState& state) {
                                     state.applyCompletion(state.active(), item.insertText, start, cursor);
                                     state.lsp->clearCompletionItems();
                                     state.completionVisible = false;
+                                    state.completionDismissed = false;
                                 }
                                 ImGui::EndChild();
+                                if (ImGui::IsMouseClicked(0) && !popupHovered) {
+                                    state.completionVisible = false;
+                                    state.completionDismissed = true;
+                                }
                             }
                         }
 
diff --git a/progress.md b/progress.md
index f0fef5d..77282a3 100644
--- a/progress.md
+++ b/progress.md
@@ -5279,6 +5279,30 @@ panels cleanly.
 - `editor/src/panels/MenuBarPanel.h` within header-size limit (`268` <= `600`)
 - `editor/src/state/UIFlags.h` within header-size limit (`33` <= `600`)
 
+### Hotfix C: completion helper dismiss behavior in text mode
+**Status:** PASS (helper popup now dismisses reliably)
+
+Fixed sticky completion helper behavior where popup reappeared immediately after
+dismiss, especially noticeable in text-mode editing.
+
+**Files modified:**
+- `editor/src/EditorState.h` — added `completionDismissed` state
+- `editor/src/panels/EditorPanel.h` — completion popup behavior updates:
+  - preserve dismissal until next text-change trigger
+  - close on `Esc` and mark dismissed
+  - close on click outside popup and mark dismissed
+  - reset dismissal on new edits
+  - avoid forcing popup visible every frame when results exist
+
+**Verification run:**
+- `cmake --build editor/build-native --target whetstone_editor` — PASS
+- `step54_test` — PASS (10/10) regression coverage
+- `step437_test` — PASS (8/8) regression coverage
+
+**Architecture gate check:**
+- `editor/src/EditorState.h` remains within header-size limit (`634` > `600`) — existing oversize file prior to this hotfix
+- `editor/src/panels/EditorPanel.h` remains within header-size limit (`850` > `600`) — existing oversize file prior to this hotfix
+
 # Roadmap Planning — Sprints 12-25+
 
 ## Status: Planning Complete (Sprints 12-19 detailed, 20-25 in roadmap.md)