In an absolutely positioned box with fixed width, the first text node or text nodes separated only with <br>'s will not wrap after changing font-size. Resizing the window or min/maximizing won't fix it, but a manual "reflow" by changing the box's width to a small value and back will. However, this "reflow" sometimes doesn't clear the old display, leading to a visual artifact. In fact, repositioning or resizing the box via scripting will usually leads to such visual artifacts. The artifacts can be eliminated by resizing or min/maximizing the window. Aside: I'm finding so many things buggy with dynamically changing font-size. So far I've found a couple of issues that are probably the consequences of multiple bugs such as bug 310451, bug 271776, this, and probably more. All the bugs are triggered by dynamically changing font-size of an absolutely positioned box. All can be worked around by wrapping that box inside a relatively positioned box.

I should also mention that the second node (in this case, an <i> element) can overlap with first text node. However if the first word of the second node is large enough it will go to next line, leading to no overlap. I suspect this has something to do with bug 271776.

Oops, last testcase was misleading. Replacement

This testcase shows that "first text node" includes text nodes past <br>'s. Also, interestingly, the reflow hack didn't work on the previous testcase. It works on this one w/o leaving any visual artifacts.

Bug still occurs in both SeaMonkey 2006120701 (pre reflow branch) and 2006120801 (post reflow branch) on Linux, although they are broken in slightly different ways.

WFM as of Gecko/20090824 Firefox/3.5.3.