Okay, I am sending you my files:
2 XSLT files and one XML file (please see attachment).
You should select MSN_WowAttributes in the scenario properties.
As I see, just an XSLT extender function is something unusual.
Maybe it causing the problem.
My exact steps to reproduce the problem:
1) I put a breakpoint at <xsl:call-template name="WatchTemplate">
2) I launch debugger for a few loops, including F11 steps.
3) I stop debugger pressing 'stop debugging (Shift-F5) button on the toolbar.
4) I make a textual change to the XSLT file.
5) I am trying to save adjusted XSLT file.
6) The error pops up.
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