Dears, We observed this issue under galaxy release 15.07. Tools with a param tag and type="data_column" in their xml file are impossible to set on a workflow "run" mode. The value of the column stay at "column 1" or void even if your tabular file has more than one column.
The setting of the tool is ok in the "analyze data" mode : you can change the value of the column.
We tested this issue with home made tools but also with Merge Columns (version 1.0.1) tool - "text manipulation" section on our Galaxy instance. and we detected the issue on the galaxy main instance too...
Any idea ? Thanks Marion & Franck