comment-region emacs function inverts text highlighting

[chalaev]

When I comment a line with comment-region emacs function, the text highlighting below this line is inverted:
comments are shown in the way that commands should be, and vice versa.
Note: I comment the line by selecting it pressing F4, which is bounded to the comment-region function in my ~/.emacs file: (global-set-key [f4] 'comment-region)
Emacs : GNU Emacs 24.4.1 (x86_64-pc-linux-gnu, GTK+ Version 3.14.5)
of 2015-03-07 on trouble, modified by Debian
Package: gnuplot-mode (version 0.7-beta)

[conao3]

This issue still remained?