[show-hint addon] Don't close completion when text is moved

Closes codemirror#3849

Author: marijnh

addon/hint/show-hint.js

@@ -121,11 +121,13 @@
 
     finishUpdate: function(data, first) {
       if (this.data) CodeMirror.signal(this.data, "update");
-      if (data && this.data && CodeMirror.cmpPos(data.from, this.data.from)) data = null;
-      this.data = data;
 
       var picked = (this.widget && this.widget.picked) || (first && this.options.completeSingle);
       if (this.widget) this.widget.close();
+
+      if (data && this.data && isNewCompletion(this.data, data)) return;
+      this.data = data;
+
       if (data && data.list.length) {
         if (picked && data.list.length == 1) {
           this.pick(data, 0);
@@ -137,6 +139,11 @@
     }
   };
 
+  function isNewCompletion(old, nw) {
+    var moved = CodeMirror.cmpPos(nw.from, old.from)
+    return moved > 0 && old.to.ch - old.from.ch != nw.to.ch - nw.from.ch
+  }
+
   function parseOptions(cm, pos, options) {
     var editor = cm.options.hintOptions;
     var out = {};