The “Visits by Server Time” widget does not appear to produce a complete graph on start-up in Piwik version 1.8.4. It’s OK in earlier versions.
When the widget starts, the graph produced (I only tried the bar graph and the pie chart) only displays the time range from midnight to 9 am. The rest of the graph is missing. When I maximize the widget’s display, the incomplete graph is still incomplete.
The “incomplete graph” takes up the whole width of the space allocated. It’s as if the widget had been configured to display only the time range from midnight to 9 a.m.
When I change the graph type (from bar graph to pie chart, for example), the whole 24-hour time range will appear in the new graph. When I then change back to the original graph type (from pie chart to bar graph, in this example), the entire 24-hour time range is properly displayed.
It does not matter whether the “Visits by Server Time” widget starts with a bar graph or the pie chart – the behaviour is the same.