improve dialog and cloud browse icon text, deselect guide on mode leave

src/canvas_modes.h

@@ -137,12 +137,13 @@ class CanvasModeGrid : public CanvasMode
     std::unique_ptr<class ActionModeGrid> m_action;
 public:
     bool m_highlight = false;
-    int m_selected_index;
+    int m_selected_index = -1;
     std::vector<ray_t> m_lines;
     virtual void on_MouseEvent(MouseEvent* me, glm::vec2& loc) override;
     virtual void on_KeyEvent(KeyEvent* ke) override;
     virtual void on_Draw(const glm::mat4& ortho, const glm::mat4& proj, const glm::mat4& camera) override;
     virtual void init() override;
+    virtual void leave(kCanvasMode next) override;
     void commit();
     void clear();
 };