I believe mouse and keyboard events were lost during the transition from Web 1.0 to 2.0. If I remember correctly, it had to do with some performance issues due to the need for lots of round trips between the client and the server. I don’t know how much of this got rectified.
For a while @Tim_Parnell had a product that brought them back, but I believe it’s now EOL’d.
@Anthony_G_Cyphers has a solution that still stands today in GraffitiSuite Web Edition with the GraffitiEventManager.
Others can probably fill in more here and correct anything I said that might be a bit off kilter.