OTSManager.destroyControl(controlHandle);
OTSManager.destroyControl(ctx.getControl()); ctx = null;
OTSManager.destroyControl(ctx.getControl()); ctx = null;
OTSManager.destroyControl(ctx.getControl()); ctx = null;
OTSManager.destroyControl(ctx.getControl()); ctx = null;
OTSManager.destroyControl(controlHandle);