A workaround has been discovered to prevent the Windows Phone 7.5 keyboard from disappearing.
Microsoft confirmed on Monday that it is currently investigating reports of the Windows Phone 7.5 keyboard disappearing. A number of users have reported that the Windows Phone 7.5 “Mango” keyboard disappears during regular use of the phone. A thread on the XDA-developers forum contains 40 replies of users complaining about the issue. “The keyboard just drops when I’m texting,” notes one poster. “It’s almost as if the screen was registering another touch on the messaging hub making it the keyboard drop. I don’t really know, but it was annoying.”
One French Windows Phone developer has discovered the root of the problem. The disappearing keyboard appears to be related to Windows Phone’s “background agents”. Greg Fonta created a video of the issue (see below) to prove it was related to a new Windows Phone 7.5 feature. Scheduled Tasks or Background Agents allow an application to execute code in the background, even when the application is not running in the foreground. HTC devices include a background agent for the Hub and a number of third party applications utilise the support to update Live Tiles and other parts of applications. WMPU reports that disabling individual background tasks appears to fix the issue.
Windows Phone 7.5 users can disable the tasks by navigating to Settings>System>Applications>Background tasks, and switching off tasks on a per application basis. WinRumors has reached out to Microsoft to clarify whether the technique is a recommended workaround.