If you want to hide the IBM Connections “Activity” sidebar as you install a Lotus Notes client you need to add the following parameter to the PLUGIN_CUSTOMIZATION.INI file of the client package:
com.ibm.rcp.ui/HIDE_PANEL_com.ibm.workplace.ae.client.views.AESideShelfView=true
I did not find that documented somewhere and it took quite a while to solve this, so maybe someone else is looking for that as well …