Edit the toolbars.cfg file for the skin that you use and find the following code.
%ifplugin history
History{
history(View)|Histor&y
View History. Right-click for more options.
toolhot.bmp[12]
toolcold.bmp[12]
tooldead.bmp[12]
}
%endif
Change the code to look like this.
# %ifplugin history
# History{
# history(View)|Histor&y
# View History. Right-click for more options.
# toolhot.bmp[12]
# toolcold.bmp[12]
# tooldead.bmp[12]
# }
# %endif
Save the file and restart KM. The # symbol makes each of code just a comment and they are not acted upon.