Ok, yeah. The problem actually lies with the plugin for *nix and how it works. I encountered this one like... four years ago, surprised it's still not fixed... wait, Open Source OS... I'm not surprised at all. Unless it's trendy/flashy or someone sets up a bounty, it will never be fixed.
The problem is that under X11 the framebuffer for plugins is allocated at a fixed size when you initialize it -- so even of the object or embed tag's block in the browser is enlarged, there's no way for the browser to report that to the plugin in that environment -- it's REALLY stupid. Worse, until you click to activate the plugin, a plugin in that environment cannot have 'focus' -- and when the plugin receives focus, the browser element loses hover and/or focus. Even just mousing over the plugin actually makes the BROWSER lose focus, much less the element itself.
Part of why X11 implementations still feel like buggy broken toys to me -- and certainly not useful so far as desktop OS use is concerned.
Just checked, Opera on *nix has the same behavior as does Konqueror, so it's much more likely an issue with how the flash plugin works than with the browsers themselves... Works just fine on Windows and OSX here... Hell, even seems to work in iCab.