Thank you for contacting us. This is the default browser behavior and we'll consider possible resolutions to it. Meanwhile as workaround you can use Chrome version 52 or higher where backspace functioning only as backspace. You can use Firefox too but in order to change the backspace behavior in Firefox navigate to about:config and change browser.backspace_action to 2.
Telerik by Progress
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items