I think the critical part that I omitted is that the main development
window must be made fairly narrow, either before starting the process of
docking a number of tools side by side or after.  For example, I just
now tried docking about 5 tools side-by-side at bottom of the main
development window.  No problem occurred.  CPU and memory were normal
and the ec process seemed to be inactive.  Then I resized the main
development window to make it very narrow and estudio started redrawing
over and over and using more and more memory.