Tagging set subset doesn't work as expected

[ndevenish]

If I tag a portion of a set's files I'd expect:

data files th_8_2 subset

to give me the files in set th_8_2 with the tag subset. Not sure what was originally intended, but this doesn't work and gievs the confusing output:

$ data files th_8_2 subset
/Users/nickd/dials/datasets/th_8_2/th_8_2_0001.cbf            Tags: /Users/nickd/dials/datasets/th_8_2/th_8_2_0023.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0049.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0016.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0097.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0021.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0062.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0077.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0036.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0082.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0022.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0017.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0060.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0066.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0011.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0067.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0081.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0088.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0013.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0065.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0099.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0094.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0037.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0005.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0058.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0056.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0080.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0075.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0054.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0029.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0078.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0014.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0064.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0025.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0057.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0018.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0009.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0059.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0092.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0006.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0079.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0090.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0033.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0004.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0045.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0038.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0083.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0068.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0093.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0047.cbf, subset, /Users/nickd/dials/datasets/th_8_2/th_8_2_0010.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0091.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0027.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0044.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0003.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0098.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0089.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0050.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0048.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0046.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0085.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0040.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0026.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0035.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0041.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0087.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0020.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0015.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0043.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0070.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0008.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0051.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0084.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0019.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0072.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0030.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0007.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0086.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0034.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0032.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0024.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0052.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0071.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0042.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0069.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0095.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0031.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0073.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0039.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0053.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0074.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0055.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0096.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0002.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0076.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0028.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0063.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0012.cbf, /Users/nickd/dials/datasets/th_8_2/th_8_2_0061.cbf

e.g. all of the other files as tags?