restore undo buttons to main toolbar, show cursor on quick resize

src/canvas_modes.h

@@ -67,7 +67,6 @@ public:
 class CanvasModePen : public CanvasMode
 {
     friend class App;
-    bool m_draw_tip = false;
     bool m_dragging = false;
     glm::vec2 m_pan_start;
     glm::vec2 m_size_pos_start;
@@ -88,6 +87,7 @@ public:
     virtual void leave() override;
     bool m_picking = false;
     glm::vec2 m_cur_pos;
+    bool m_draw_tip = false;
 };
 
 class CanvasModeLine : public CanvasMode