Warning: Invalid argument supplied for foreach() in ..../piwik/plugins/Dashboard/Controller.php on line 151
shows up for each empty dashboard column; so if one column has a widget there are two warning messages, 2 widgets on 2 different columns gives only 1 warning - no widgets at all shows 3 messages.
using latest version 0.5.4
Keywords: empty dashboard
Is this a new install?
This shouldn't be possible if the dashboard layout was saved correctly.
(In ) fixes #1100 - handle malformed dashboard layout
Post-note: the cause was json_decode() for an empty array element ('') did not return array().