# #8 Only the Changed Part If the backend sends the view on every request — [#5](/advanced/insights/05-ui5-over-the-wire) — does the screen rebuild itself on every click? It would, and the user would notice within about two seconds. A rebuilt view is a new set of controls: the cursor leaves the field, a half-typed entry is gone, the table scrolls back to the top. Nobody wants to type into that, and no amount of "but the architecture is elegant" survives a user typing a customer name three times. So the view is not sent every time. Sending it is a decision the app makes: ```abap METHOD z2ui5_if_app~main. me->client = client. IF client->check_on_navigated( ). set_view( ). " first display, and every return from a sub-app RETURN. ENDIF. IF client->get_event( ) = `COUNT`. count = count + 1. " changes the model - and nothing else happens ENDIF. " no set_view( ) here: the response carries the model alone ENDMETHOD. ``` `count` is a public attribute bound to a `Text` in the view. Every press of the button runs `main( )`, and `main( )` changes a number and returns. When `set_view( )` is not called, the response carries the model alone. The view in the browser is the one already standing, and UI5 does what UI5 does with a changed model: data binding updates the controls bound to what changed, and touches nothing else.  *What a response carries decides what survives on the screen.* The DOM is not rebuilt. Focus stays in the field. The scroll position holds. The value the user is halfway through typing survives, because the input control was never replaced — only its bound value was. This is what the Over-the-Wire frameworks outside SAP do with HTML fragments, and the pleasant part is that UI5 gives it away for free, through a mechanism that was in the framework long before this one existed. No diffing algorithm, no virtual DOM, no reconciler — just a model that changed and a binding that noticed. Data binding was doing this while the JavaScript world was still inventing names for it. Sending the whole view is the exception, not the rhythm.