SYMPTOM:
A user changes the number format of a metric in a grid and switches to a graph visualization in Visual Insight. After doing so, they notice that the number formatting of the Y-axis no longer shows the expected format, in Strategy Web 9.4.1.
For instance, the following metric is formatted as currency:

However the graph's Y-axis displays as general format like shown below:

STEPS TO REPRODUCE:

CAUSE:
This is working as designed in Strategy Web 9.4.1. By default the labels are configured as condensed. When the labels are condensed they lose the formatting including any prefixes or postfixes.
ACTION
Disable the condensed format of the labels, like shown below:

After unchecking this option the graph should display the number formatting as expected, as shown below.
