Fix: scrolling the canvas screws up xlet tooltip positions

pd/nw/pdgui.js

@@ -2239,7 +2239,7 @@ function gui_gobj_draw_io(cid, parenttag, tag, x1, y1, x2, y2, basex, basey,
             xlet_class = "xlet_control";
             xlet_id = tag + type + i;
         }
-        if (k12_mode === 1) {
+        if (k12_mode === 1 && type) {
             xlet_class += " xlet_tt" + type; // used to determine the position of the tooltip
         }
         rect = create_item(cid, "rect", {
@@ -2287,7 +2287,7 @@ function gui_gobj_configure_io(cid, tag, is_iemgui, is_signal, width) {
         } else if (is_signal) {
             type = "xlet_signal";
         } else {
-            "xlet_control";
+            type = "xlet_control";
         }
         e.classList.add(type);
         e.classList.remove("xlet_selected");
@@ -2300,23 +2300,32 @@ function gui_gobj_configure_io(cid, tag, is_iemgui, is_signal, width) {
 }
 
 function gui_gobj_highlight_io(cid, tag) {
-    gui(cid).get_elem(tag, function(e) {
-        e.classList.add("xlet_selected");
-        if (k12_mode === 1
-            && (e.classList.contains("xlet_tti") || e.classList.contains("xlet_tto"))) {
-            gui(cid).get_elem("xlet_tt", function(tt) {
-                var e_rect = e.getBoundingClientRect(),
-                    e_x = e_rect.left,
-                    e_y = e_rect.top;
-                tt.innerHTML = k12_xlet_tt[e.parentNode.getAttribute("ttid")][tag.slice(-2)];
-                tt.style.display = "block";
-                tt.style.left = e_x + 10 + "px";
-                if (e.classList.contains("xlet_tti")) {
-                    tt.style.top = e_y + 3 + "px";
-                } else {
-                    tt.style.top = e_y - 10 + "px";
+    gui(cid).get_nw_window(function (nw_win) {
+        var xlet = nw_win.window.document.getElementById(tag);
+        if (xlet) {
+            xlet.classList.add("xlet_selected");
+            // for K12 abstraction xlets, show tooltips at mouse position
+            if (k12_mode === 1
+                && (xlet.classList.contains("xlet_tti") || xlet.classList.contains("xlet_tto"))) {
+                var tt = nw_win.window.document.getElementById("xlet_tt"),
+                    xlet_rect = xlet.getBoundingClientRect(),
+                    xlet_x = xlet_rect.left,
+                    xlet_y = xlet_rect.top,
+                    win_left = nw_win.window.document.body.scrollLeft,
+                    win_top = nw_win.window.document.body.scrollTop,
+                    abstraction_tt = k12_xlet_tt[xlet.parentNode.getAttribute("ttid")];
+                if (abstraction_tt) {
+                    tt.innerHTML = abstraction_tt[tag.slice(-2)];
+                    tt.style.display = "block";
+                    tt.style.left = xlet_x + win_left + 10 + "px";
+                    if (xlet.classList.contains("xlet_tti")) {
+                        tt.style.top = xlet_y + win_top + 3 + "px";
+                    } else {
+                        var tt_height = tt.offsetHeight;
+                        tt.style.top = xlet_y + win_top - tt_height + "px";
+                    }
                 }
-            });
+            }
         }
     });
 }