Calender alignment in Firefox 6.0 (height of text to small)

I found a minor issue with Project'or RIA Version 1.6.2, in combination with Firefox 6.0

The planning alignment is somehow wrong: the activities (and milestones and so on) are a little less high (1 or 2 pixels) than the rest of the calendar. This leads to a false alignment of the calendar: the corresponding timeline (chart) for the activity does not exactly line up behind the activity text. For the first activities this is not a big issue, however, with more activities it gets hard to identify text with the corresponding timeline.

If desired I could make a screenshot for you.

In Internet Explorer 8 this does not occur.

Screenshots:

Correct in Internet Explorer 9.0.2:
tweakers.net/ext/f/KFebA7YvmyvGuQ65QwzZp...ull.png?nohitcount=1

False in Firefox 6.0:
tweakers.net/ext/f/nmdZDzBhaFE5Um4bkRJXT...ull.png?nohitcount=1

(I hope the images are accessible)

I tested this with Release Candidate 1.7.0 too, and also in that version this occurs.

I hope I have given you enough information to work with.

Confirmed; when the browser cache is cleared the problem is solved.