The module doc says that the "Gimp" module "Listens to all instructions and says nothing" but gives no explanation for why that would be necessary or useful and it is not mentioned anywhere else in the docs. The wiki also turns up nothing, nor does searching here on splunk answers. Yet it is included in the advanced XML generated by the dashboard editor, so it seems like it must have a purpose.
This module is used by Splunk 5.x Simple XML to gather context settings at the bottom of an Advanced XML tree for use by the Simple XML Panel Editor. The Simple XML Panel Editor requires key/value parameters in a certain format, and the Gimp Module is inserted into the context to pick up settings passed down from all the modules in a given tree and remap them into the form which the Simple XML Panel Editor requires.
In Splunk 5.x, Simple XML was effectively an abstraction on top of Advanced XML. When a user created a Simple XML dashboard, behind the scenes an Advanced XML dashboard was created, and things like Gimp and Viewstates were inserted automatically as part of the translation. I am 99% sure you added ?showsource=1 to the URL of a Simple XML dashboard in order to find the Gimp module, correct?
In Splunk 6.x, Simple XML is no longer an abstraction on top of Advanced XML, but rather an abstraction on top of a discreet set of dashboard components that are not arranged hierarchically.
Yes, I used "showsource=1" in the URL of a dashboard made with the Simple XML Panel Editor to see it, in addition to seeing it in the generated module docs.
Thanks you for confirming that it was there to support the Simple XML application and was not necessary when working with Advanced XML directly; I suspected as much.
So if I understand you correctly, the "ViewstateAdapter" module is also unnecessary in Advanced XML?
Yeah, the ViewstateAdapter was an older technique for setting and retreiving view-specific settings in Advanced (and Simple) XML. I can't think of any Advanced XML view that implements viewstates explicitly.