I've been using the Windows 8.1 Preview and liking it, but noticed that the flow of doing a search in an app has changed. When searching for something in an app, Windows 8 would launch an app-specific search results page. In 8.1 it launches the Bing search results page. Say I'm looking for a mail, I can't find it straight away using Search from the Charms. I have to click the drop-down and select the current app, like so (picture shows MetroTwit):
I guess Microsoft wants developers to have a visible search box, like how they did with the Mail & Store app. Still it bothers me for apps like MetroTwit (and many others) that don't do this. It took me some time to figure out the drop-down, and it still is an additional step for something basic like finding an email or searching tweets in a Twitter app.
Now you have to open an app first and then perform a search, you have to know what app you need to be in. In Windows 8 you could enter a search term anywhere, and easily jump around between apps by clicking on them in the right-hand list. Seeing a new word, type it in the search box, click on a translate app to translate the word, click on the Wikipedia app to learn more about it, click on a Twitter app to search tweets about that word, those things all went very smoothly in Windows 8. in 8.1 I have to find the app, perform the Search, select the app from the drop-down, go back to start, open another app, perform the search again, select the app from the drop-down, and on.
On an additional note, the Windows Store doesn't even list the app in the Search drop-down, you have to use the search box in the app. (again no big deal but my brain is hardwired to go to the Search charm by now). I feel like the Search charm is being downplayed to be used only for files, settings and web results and not for individual apps. (I really loved having an app list all the time when doing a Search in Windows 8 and easily search around between apps)