After upgrading windows 10 1703 or newer, we found that there is a big change in Microsoft Pinyin IME. 

 

We are implementing many TSF interfaces in Windows client. In the trace log, we found that the new Pinyin IME calls many times BeginUIElment interface, even there is no any input. For example, just get focus, it will still call BeginUIElement interface. This impacts our system performance...

 

Moreover, when we start typing some characters, such as "nihaozhongguo", when press Space key to select composition strings, for example, we select "你好", then it shows "你好zhongguo" as expected. But in our system (implemente TSF interfaces), after pressing Space key and select composition strings, it will only select “你好”, there is no any candidate window leave there, which seriously breaks our input implementation. BTW, what could make the candidate window disappears?

 

So, we want to know what is happening in this case (call sequences change, interface calls change or miss some interface calls). Then we could also change our interface implementation to support windows 10 1703 Microsoft Pinyin IME.