@ArslanA
I sympathise with your situation - Sencha has often been difficult to get timely responses from, I find. However, I wonder if this issue can be tackled from another perspective:
I appreciate this is not trivial, but would it be worth the effort to revisit your iframe approach - try to load Ext.NET components dynamically during an AJAX request, or through Direct Events instead of loading iframes? It may help provide an even slicker experience for your end users while by-passing some of the memory leak issues?
Although it does seem Sencha has a memory leak issue with iframes, even if that is sorted out, or you switch to another framework altogether, heavy use of iframes could still be an isuse. For example,
- The browser itself will still have to manage many iframes, which will still require more memory;
- Your pages might have to download more HTML/CSS/JavaScript than necessary (not always) and you may need to end up writing iframe cross communication code which can be annoying/messy (though Ext.NET's message bus may help I suppose);
- If your iframe contents are creating more Ext.NET based pages, various Ext.NET/Ext JS initialization will need to occur again, and possibly re-download script already downloaded in the main frame (though caching of course helps, but doesn't take away browser parsing/processing/interpreting of such scripts).
In an app I work on in my workplace, we have a mix of loading iframes in tabs/windows and dynamically loading Ext.NET components during AJAX requests and insert them into tabs/windows during AJAX requests, DirectMethods and DirectEvents, etc. The latter is far slicker. The only reason we still have those iframes-based approaches is they are very time consuming to convert into Ext.NET components (complex functionality and low priority) but we definitely want to do it (and have started to do so).
I also sympathise with your feeling to consider another solution - but the weeks/months of work using a different library and migrating everything across, could that similar effort be spent in not relying on iframes in first place? (I know, it is easy for me to say it here but I know it is hard to do in reality. Even in my example above we have challenges in converting some iframe-based pages into components - mostly a time constraint though...!)
All that being said, I do hope Sencha can solve this soon, because our giant app at work is still 1.x and while we have approval to migrate to 2.x we haven't prioritised it yet, but this would be a potential issue for us, too.
Hope that helps in some way :)