Beamer in Lyx 2.1 with Cyrillic letters

[Sergey]

Hi,

Recently I installed LyX 2.1.1 and noted a problem using
Beamer with Cyrillic letters.
Beamer files created wth the 2.0.x version were compiled
correctly in the latest version of LyX with XeTeX compiler.
However, any new beamer file created could not be compiled
correctly with XeTeX.
I did not try PdfLatex since all my course slides were
prepared and worked with XeTeX in the older versions of LyX.

I experience the following when using Xetex:

- Frame with text only in Cyrillic and/or Latin is compiled
correctly.
- Frame with ERT that loads files like .png, .jpg, .pdf or
pdf_tex (with \includegraphic or \input) and Latin text
before or after the ERT compiles correctly.
- Frame with ERT that loads files like .png, .jpg, .pdf or
pdf_tex (with \includegraphic or \input) and Cyrillic text
before or after the ERT does not compiles correctly, no
Cyrillic character is displayed in the PDF.
- ERT with \caption after \includegraphic does not allows
writing in Cyrillic. It does not display anything, like the
keyboard is locked. If I change to Latin keyboard,
everything is OK.

If helps, LyX 2.1.1 Bundle version was installed on fresh
Win 7 64 bit, with the latest MikteX updates.

Any suggestions?