Generally in OWB the job check_service must be running to monitor the control center service.
If the job check_service find the control center not running it will issue run_service to start the job.
Bou this should not stop you to connect to design center.
Now to resolve your issue i would like to know the following:
1)Are your OWB services(control center service) going down frequently?
2)What is the error that you are getting while connecting to design center?
If the issue is from a specific client, then as quick solution you can resinstall the OWB client in that and check the connection again.
If the issue is still happening or the issue is from all the clients the need to find the root cause:
My suggestion would be to open a SR with Oracle Support.
Some info on debugging this issue:
->Generate the OWB client trace and get the log to see any helpful info on the issue.
Metalink note 943928.1 lists the steps to generate OWB client trace in 11.2
->Check whether all the Java based clients (like SQL developer) are able to connect to the server.
->Check the listener log on the server side to check whether connection from OWB client is success or not.
Location of the file listener.log: <ORACLE_BASE>/diag/tnslsnr/<server-name>/listener/trace
->Also check the network related issue like the server is raechable from client, are ports required for connection opened etc..