EXTJS rtl grid column header alignment issue with row

I use EXTJS [rtl version] 4.2.2, my gridpanel alignment of header and rows destroyed when horizontal scrollbar appear.

everything good before add more columns to grid or resize browser:

5IUCp.png

and after add more columns or resize browser :

yq3i7.png

i test some solution but not works anyone. but i found when resize browser window and vertical scrollbar appear with horizontal scrollbar , problem solved.