Fix issue in IE where the context menu hack might stay visible

Because JS seems to be frozen entirely while the context menu is
open, the next open might happen before the timeout was able to
fire. This forces the previous context menu kludge to be cleared
before starting a new one.

Author: marijnh

src/input/TextareaInput.js

@@ -264,6 +264,7 @@ export default class TextareaInput {
 
   onContextMenu(e) {
     let input = this, cm = input.cm, display = cm.display, te = input.textarea
+    if (input.contextMenuPending) input.contextMenuPending()
     let pos = posFromMouse(cm, e), scrollPos = display.scroller.scrollTop
     if (!pos || presto) return // Opera is difficult.
 
@@ -287,7 +288,7 @@ export default class TextareaInput {
     display.input.reset()
     // Adds "Select all" to context menu in FF
     if (!cm.somethingSelected()) te.value = input.prevInput = " "
-    input.contextMenuPending = true
+    input.contextMenuPending = rehide
     display.selForContextMenu = cm.doc.sel
     clearTimeout(display.detectingSelectAll)
 
@@ -308,6 +309,7 @@ export default class TextareaInput {
       }
     }
     function rehide() {
+      if (input.contextMenuPending != rehide) return
       input.contextMenuPending = false
       input.wrapper.style.cssText = oldWrapperCSS
       te.style.cssText = oldCSS