By the way, the example in the documentation for SynchronousUpdating is not correct since it uses Pause[6] in the Manipulate example. However,
In[6]:= Options[$FrontEnd, DynamicEvaluationTimeout]
Out[6]= {DynamicEvaluationTimeout -> 6.}
So the example in the documentation for SynchronousUpdating does not show the issue. A better example would be
Manipulate[Pause[7]; x, {x, 0, 1}]
I submitted a documentation bug report for this...
