Reactive extensions – WPF fold/unfold

I have just implemented WPF fold/unfold functionality using Reactive Extensions Framework (RX). Desired algorithm is to "unfold" wpf window, as soon, as mouse entered, and "fold" after 5 seconds of mouse leaving.

First, naive implementation:

This implementation contains a bug, when you move mouse in/out several times in 5sec interval, window can left collapsed, because old "collapse" events will arrive, after delay.

Here is RX implementation, that discards "fold" messages, as soon, as new "fold" messages has arrived:

Reactive extensions for javascript.

Microsoft has released Rx extensions for Javascript. It's a great tool for organizing events processing in yours UI code.

I have used it to handle following task: Call Ajax-Update every 5 seconds, after filter button clicked and on paging request, but only when previous request is finished. Tricky? Good luck debugging it later.

This can be implemented using Rx extensions. In that case all that interactions became explicit and clear, placed on few lines of code.

Here is an example: