OK - progress has been made. On last nights build from Github, the behavior only occurs on the F3 template. OR more accurately, I know it does not occur on the default template but does occur on F3.
Following errors are generated - the first "Uncaught" error appears as the page is rendered. The rest occur when the record number dialog is clicked after entering a new rowcount.
Uncaught TypeError: Function.prototype.apply: Arguments list has wrong type
mootools-ext-min.js:1
TypeError
mootools-ext-min.js:1
TypeError
mootools-ext-min.js:1
TypeError
mootools-more.js:33Uncaught TypeError: Function.prototype.apply: Arguments list has wrong type
probably worth mentioning that on the default template, any formatting defined in a class defined in the "Use as row class" option is lost when the list refreshes after changing the rowcount.