After last week's post, I've now completed editing of module parameters in a modal popup. Edit icons appear next to the module titles which can be clicked to edit the module parameters. I've deliberately disallowed editing of advanced and other parameters from the modal popup at the front-end to avoid complexity. If it is a custom HTML module, then its content can also be edited via the modal popup.  

There are bugs in article & module editing which I'll be fixing in the coming weeks along with adding support for IE and other browsers.
As bobbravo2 pointed out, I'm not sure if the edit icons should be hidden/revealed when editing is toggled or the toggle function should only work for enabling/disabling of editing of titles in-place. The only reason a user will click an edit icon is if she wants to edit the article/module. But then, it makes sense to either enable or disable editing completely rather than partially. I would like your point of view on this. 
I'm not sure if I can implement in-place editing any other way ( other than the current way of background-color on hover and clicking to edit ) which will not interfere with the template and at the same time be user-friendly. I don't want popups to be clogging the UI every time you hover over a title as it will be difficult to ascertain the right position where the popup should appear ( template dependent ).
To make it easier to enter or leave editing mode, I've implemented a shortcut key 'e', using which you can toggle editing On/Off. So, anytime you want to perform editing, just press 'e'.
The next task I'll be taking up is of drag & drop placement of modules. Hence, in the coming week, I'll be fixing bugs plus starting up with drag & drop placement of modules.