diff --git a/web/source/osk/browser/keytip.ts b/web/source/osk/browser/keytip.ts
index 47ba68acff..19c62edfe1 100644
--- a/web/source/osk/browser/keytip.ts
+++ b/web/source/osk/browser/keytip.ts
@@ -31,7 +31,9 @@ namespace com.keyman.osk.browser {
       let util = keyman.util;
 
       // Create and display the preview
-      if(on) {
+      // If !key.offsetParent, the OSK is probably hidden.  Either way, it's a half-
+      // decent null-guard check.
+      if(on && key.offsetParent) {
         // The key element is positioned relative to its key-square, which is,
         // in turn, relative to its row.  Rows take 100% width, so this is sufficient.
         //
diff --git a/web/source/osk/inputEventCoordinate.ts b/web/source/osk/inputEventCoordinate.ts
index 178733e8c0..62de3edde5 100644
--- a/web/source/osk/inputEventCoordinate.ts
+++ b/web/source/osk/inputEventCoordinate.ts
@@ -50,8 +50,8 @@ namespace com.keyman.osk {
     }
 
     public get activeInputCount(): number {
-      if(window['TouchEvent'] && this.source instanceof TouchEvent) {
-        return this.source.touches.length;
+      if(window['TouchEvent'] && this.source['touches'] !== undefined && this.source['touches'] !== null) {
+        return this.source['touches'].length;
       } else {
         const event = this.source as MouseEvent;
         return event.buttons > 0 ? 1 : 0;