The EJ2 grid(bootstrap) dialog in IE mobile view is missing the scroll bar and hence not able to navigate to the bottom elements for accessing inputs. This is happening in IE 11 and the same mobile view (Browser window resized to mobile view) in chrome works fine though. The scenario to reproduce issue is as follows
1. Go to your demo site (https://ej2.syncfusion.com/aspnetmvc/Grid/DialogEditing#/bootstrap) in IE 11
2. Resize to mobile view and refresh the page
3. Then click on the Add button and see the scroll bar missing in IE 11
I am attaching the screenshots for both IE as well as chrome for your reference. The same issue happens for our application too.