run the attached example in FL >= 7.0.5.FL.20150128-Eval (does not happen yet in 7.0.5.FL.20150127-Eval) and resize the window.
I recorded a video to show a JS profiling (without the profiler the execution is faster, still a CPU peak is noticeable)
http://screencast.com/t/zJx7Gsi1QEr
The length of the loop exceeds the UI complexity by several orders of magnitude, with a more complex UI the resizing easily results in JS stack overflow errors)

WORKAROUND:
the correct usage (removing the width="100%") does not cause the issue (commented out line 6 in the example).
Still the code should not cause endless loops/stackoverflows, and rather warn the user about incorrect usage. This is likely going to happen in different use cases, and in general difficult to debug.