Product:
Cognos Planning version 8.4.1

Symptom:
The handles are not expandable inside the Cognos Planning Contributor client.

Cause:
Rich Client Contributor front-end have the expand/collapse (plus/minus) handles for hierarchies.

This is controlled by this Hierarchical Dimensions in Analyst

For a dimension to be shown as a hierarchy in Analyst, the following requirements need to be met:
• The dimension must not be a time dimension.
• The dimension’s items must all be detail or simple sums.
• Do not use weighted or time averages.
• Do not use the Force to Zero calculation option.
• Priorities can only be 0 or 10.
• Do not use any formatting.

Solution:
Recreate your Cognos Planning application to only use above allowed values / properties.