I fixed several often-reported bugs of 0.45:

* Exporting blurred objects to bitmap is now much faster. This was particularly slow in 0.45; some files could take hours to export. Now this is fixed, in part by the faster algorithm (contributed by Jasper soon after the 0.45 release) and in part by today's bugfix in the export code. Now even the quite complex files with large blurs export at high resolution in at most a few minutes.

* The disappearing of blurred objects in exported bitmaps which happened for large objects in 0.45 is fixed.

* The same fix got rid of the rendering artefacts that sometimes appeared on blurred objects during scrolling.

While the fix is simple, it's in a sensitive area, so please test rendering and exporting your files with blur and report any problems to me at once!