Thisarticle:
http://msdn.microsoft.com/en-us/library/ff967563(v=vs.92).aspx
describes how to add an application to Share option in picture viewer.
I would like to do the same with Office documents.

having come from iPhone and loving my WP7.5 device, i miss the threading of calls. example you call Mr. Smith 6 times and he calls you twice, have them collapsed into a list that you can expand, this reduces the size of the list and lets your be more organized. searching by missed, Called, and all would be great at well.

动态壁纸，或者和WIN7一样的幻灯片壁纸。 希望微软多用一些透明效果。 在软件栏可以分栏软件，而不是用搜索软件名的方式。

Allow the user to send video in an MMS message. In mango, only sharing via email is supported.

Business man uses two phones for their works and private.

Nowadays, there is a lots of Dual-Sim supported phones. Android support dual-sim architecture on their OS level. But WP8 doesn't.

to enter just numbers, with no additional simbols but "+", "-" and "."
would be great a "-->" as tab to jump to the next textbox. Business Apps usually have that kind of needs.

At the moment, the periodic task runs every 30 minutes. My suggestion is to make this interval configurable. For example, if you want to retrieve gelolocations frequently in the background. It is just not possible to do this at the moment. Other platforms (iOS and Android do support this!!!!!). Let the user decide what he wants (concerning battery life etc). Don't define restrictions for developers.

I am very intersting in develop app in WCF that let me to receive notificaction from the server or other clients, but this is impossible for three main reasons:

1.- WiFi is disabled when the phone is locked.
2.- It's not possible to have an app in background that listens the communication channel.
3.- WCF don't let duplex communication.

In http://msdn.microsoft.com/en-us/library/windowsphone/develop/jj206968%28v=vs.105%29.aspx , default lock screen can't change.
plz allow change in xml, thx.
BTW: Like bing app background, it can change.

It would be very useful for some audio applications to turn the speaker on while headset is connected. Especially for FM radio and other audio jack connected applications.

I mean we have got XNA running on WP7 phones, so why can't we port our XNA games onto WinRT Tablets?
It is crazy not to have a unified Phone & Tablet platform like iOS. So please ensure XNA and Silverlight platforms are available on both WP8 & WinRT Tablets

I'm betting on WP7 growing in 2012 - U need to do a MUCH better 'Job' on the TV advertising - I saw the start of the TV advert and said to myself 'Please don't let this be the new WP7 ad ' and sure as heck it was. My friends know I'm developing for WP7 and the current stuff is embarrasing. Get that Brandon bloke back !

In Microsoft.Phone.Scheduler.Alarm Class,sound property can acess "content " file ,why can not acess isolatedStorage wave file?please open api.

Font weight in Button is not working at all.

Microphone sampling frequency is fixed. So Microphone.SampleRate property just returns this fixed value. For example the HTC Mozart microphone sample frequency is fixed as 16000 Hz. It isn't useful for several intersting application.

Ability to Send SMS in code without showing SMS Composer screen

Mango supress the 'next page' link in IE menu. That's inconvenient when we press the back button accidentally or by error.