Oh no, you miss understood this part
You should NOT delete this on the template itself, but on the template used as an instance on a window YES.
I encourage to start with indirect tag bindings first to understand the concept and the jump to user defined parameters.
Also it looks like your are doing a bad binding type at the template, when you are using user defined you should you property binding, like this:
About Designer Cache:
But I think is totally unnecessary in this case since I think your missing a step somewhere.