Can you provide specific files where this is the case. I try to use 4 spaces exclusively. Only exception I can think is other open source code that I have included verbatim. Let me know where you're seeing this and I'll fix.
I agree that this is important, but it isn't a bug. I'm changing it back to a proposal.
I am brand new to jqPlot and very much appreciate your work. This issue is definitely a highly preferential thing so I agree it should definitely be filed under proposal and be weighted very low as far as importance goes.
At any rate, just to throw in my 2 cents on the issue, I actually find that I prefer tabs to spaces for my projects because I work with people would like a 4-space indent while others like 2-space or 3-space. With personal preference being something I prefer to not get into too much of an argument about, I go with tabs so that each individual developer on the project can set their tab stop in their favorite editor to whatever they prefer.
Also, in other uncompiled, html, and furthermore inferior non-minifiable languages, I find tabs to be better since it only costs 1 byte per tab in file size versus 4 bytes for 4 spaces.
All that being said, please feel free to completely ignore my comments if you see fit because, after all, this is your project and you can format the files however you see fit.
I don't care much one way or the other for tabs/spaces although you have a couple of good points about using tabs. I seem to use spaces by default only because I do a lot of python programming (where indentation has programmatic significance).
The code base started out with 4 spaces indent, so I'm not going to change in the foreseeable future. I'll clean up the tabs where I can as time permits.