OpenOCD Plugin disables Telnet and Tcl Servers
As a workaround I generated a batch file to modify the arguments like this:
@echo off
echo %1 %2 %3 %4 %5 %6 %7 %8
C:\Ac6\SystemWorkbench\plugins\fr.ac6.mcu.externaltools.openocd.win32_1.16.1.201710251246\tools\openocd\bin\openocd.exe %1 %2 %3 %4 %5 %6 %7 %8
However, it would be nicer if there were checkboxes to control the servers, or at least would not interfere. In default configuration "-c tcl_port disabled -c telnet_port disabled" can be added to OpenOCD Command box..