The RFB (VNC) protocol is odd when compared to other network graphics protocols, such as X11 and RDP, in that there is no provision for viewer-side caching of pixel data. While this makes the client easier to implement, there is a price to pay in terms of interactive response. For example, every re-exposure of a window or background region needs to have its (compressed) pixel data resent over the network. This effect is particularly noticeable for windows with complex or photo regions (such as a web browser window) that gets iconified and deiconified or re-exposed often.