Haven't encountered the issues alluded to with the colon character in Chrome/Firefox.
One important thing to realize, is that the .../Trace/All and .../Trace/Reset method is only really needed when having to debug asynchronous processing which is not directly caused by a user's client-side action, such as Timer activity and Callable Service requests. For processing which starts in user interaction using the Trace All method could be confusing, since there will usually be more than one trace file created, and the modeler will need to figure out which trace file is the relevant one.
And one more note ... The Startup-[timestamp] file is actually created automatically when the application server starts the specific application, and it's creation is not affected by the above options.
More information regarding visual debugging (tracing) can be found in http://www.tersus.com/#Id=46.
For best results, use the Firefox browser..