The 'bad stuff' from an OSS point of view is, generally, longer ago than that.
- "Embrace, Extend, Extinguish": 1995 - US vs. Microsoft Corp: 1998 - Halloween Documents: 1998
Scraping under the 15 year bar:
- Microsoft vs Sun settlements: 2001-2002 - Ballmer "Linux is a Cancer": 2001
SCO vs IBM was 2003, so I guess fits into the '10-15' ballpark, but I think "over the last 10-15 years" makes it seem more continuous than the evidence suggests. If you were to describe Microsoft's behavior over the last 10-15 years with respect to open source software, I think a fair assessment would be "improving".
I'm not, honestly, trying to be an apologist for this stuff - it was, clearly, Microsoft policy for a long time to deliberately and pretty unscrupulously undermine Linux and Java and open source adoption. It doesn't appear to be policy to compete unfairly any more, and in some cases MS is producing technologies which support usage of non-MS-originated open and open source technologies. Can we begin to move on a little?