ArcGIS Spatial Analyst Histogram tool fails with a raster rendered with a colormap

Description

** This bug is fixed at ArcGIS Desktop 9.1 **

The ArcGIS Spatial Analyst Histogram tool, on the Spatial Analyst toolbar, fails if the raster is rendered using a colormap.

Cause

Raster layers symbolized with a colormap renderer are not supported by the Histogram tool.

Workaround

1. Right-click the raster layer in the table of contents and click Properties.
2. Click the Symbology tab and click Unique Values from the list of renderers.
3. Click OK, then click the Histogram tool, making sure that the raster layer is first selected in the Layer drop-down list on the Spatial Analyst toolbar.