I'm finalizing a midsummer update (1.4.2) and I'm quite excited to tell you that I *think* I have successfully fixed the crash issue that has randomly occurred in graphics heavy widgets when swiping them to launcher. It was caused by MCompositor's (Meego's windowing system of a sorts) incompatibility with QtWebkit, but I found a fix that seems to have bypassed this issue. Here is the full changelog so far:
* Implemented possibility of choosing a preferred view mode for a widget
* Implemented progress bar and status text to indicate download and extracting progress during installation
* Implemented help text when starting app binary from shell without parameters
* Implemented mechanism to lock widgets while updating, installing and uninstalling
* Implemented cancel functionality to download phase of widget installation
* Added multiple improvements and fixes to Google Maps application
* Added version of available update to details page
* Fixed Firefox OS apps being shown in fullscreen by default
* Fixed launcher icon changing to green placeholder icon after updating a widget in PRO version
* Fixed graphics heavy apps crashing when swiping out of them
* Fixed running out of /tmp/ disk space by downloading packaged apps and updatesto /var/tmp/ instead
* Fixed local update packages being copied to tmp directory before being installed from
* Fixed downloading icons for Mozilla web apps when manifest URL contains query and/or fragment

Also, if anyone gets "Failed to extract" or "Invalid configuration file" errors while trying to install a widget, it might be caused by full /tmp/ directory. Rebooting the phone will automatically clear that directory so please give it a try. I'll implement a better model for storing temporary install files for a later version.

EDIT: Updated changelog with some new items. I discovered that Firefox marketplace changed the way it refers to app resources, which caused some issues with downloading and displaying icons for apps installed from there. Also got rid of the /tmp/ issue mentioned above.