Plug-ins delaying parts of vSphere Web Client from displaying.

Problem

When navigating to a view in the vSphere Web Client, the extensibility mechanism provides all user interface extensions to the particular extension view. From a list of potential extensions that can be displayed, the vSphere Web Client narrows down the list to the extensions that apply to the particular context by applying a set of extension filters. Some of these filters run asynchronously and delay the evaluation for all extensions when a request is sent to an unresponsive service.

The following pop-up window appears in the lower-right corner of thevSphere Web Client

Some elements could not be shown
  or their information could not be retrieved in time. Contact your administrator
  to fix the issue.

If the pop-up window is hidden, another possible issue is that a tab is displayed or not displayed for an inventory object that is not relevant.

Cause

These messages are displayed because a timeout that is now applied on the relevant computation for different user interface elements coming from vSphere Web Client plug-ins. Before the introduction of timeouts, a plug-in can cause large parts of the user interface to be delayed for 2 minutes or more. The pop-up message is displayed when any evaluation takes over 20 seconds.

Solution

When the pop-up displays, the log file (vsphere_client_virgo.log) contains an error that shows the filter that timed out and the affected extensions.

An example of the vsphere_client_virgo.log file is:

2016-06-08T20:29:07.358Z] [ERROR] http-bio-9090-exec-4 70000174
100005 200003 
com.vmware.vise.util.logging.LogServiceImpl 
Extension
filter timeout: \
vsphere.misbehaving.slowFilter/com.vmware.misbehaving.slowfilter.filters.SlowCustomFilter
could not complete execution in 8000 ms. \
Extensions
[vsphere.core.cluster.manage.slowView/com.vmware.misbehaving.slowportlet.ui:6.5.0;
] processed by the filter will not be loaded.
[2016-06-08T20:29:19.314Z] [ERROR] http-bio-9090-exec-8 70000175
100005 200003 com.vmware.vise.util.logging.LogServiceImpl Extension
filter timeout: \
vsphere.core.objectPropertyFilter/com.vmware.vsphere.client.filters.ObjectPropertyFilter
could not complete execution in 20000 ms. \
Extensions
[vsphere.core.cluster.monitor.slowView/com.vmware.misbehaving.slowportlet.ui:6.5.0;
\
vsphere.core.cluster.monitor.vsanView/com.vmware.vsphere.client.vsanui:6.5.0;
\
vsphere.core.cluster.monitor.drsView/com.vmware.vsphere.client.clusterui:6.5.0;
\
vsphere.core.cluster.monitor.haView/com.vmware.vsphere.client.clusterui:6.5.0;
] processed by the filter will be loaded.

The non-VMware plug-in can be identified as the potential issue and block it by using the new plug-in compatibility feature. Alternatively, if the issue is not obvious, you can disable all non-core plug-ins to check if the issue still persists.