Wrong candidate window position in Excel 2016

[tramhao]

Dear Author,

I'm using PIME which is based on LibIME. My environment: Windows 10 Home edition, 64 bit. Office 2016 professional plus edition, 64 bit.
The candidate windows position is wrong in excel as attached screenshot. After enter 1st letter, it's always in formular toolbar. After enter 2nd letter, it's combing back to correct location.
Similar problem observed when using Notepad++, the first position of candidate window is always on the right bottom corner which is not the current cursor position. This only happens when I tried to input the first letter after activating PIME.

After some code reading, I believe the problem is in selectionRect function in TextService.cpp, however, I don't know how to correct it. I saw some sample code from MS that they're using ITFTextLayoutSink in such situation, which is not implemented by libIME. Would you please kindly check, if this problem can be fixed? Thanks.
After some code reading, I believe the problem is in selectionRect function in TextService.cpp, however, I don't know how to correct it. I saw some sample code from MS that they're using ITFTextLayoutSink in such situation, which is not implemented by libIME. Would you please kindly check, if this problem can be fixed? Thanks.

Larry Hao