strange "lag" and cpu usage when previewing certain HTML mail in KMail

[O. Sinclair]

On 22/04/2014 15:50, O. Sinclair wrote:
> On Kubuntu 14.04 I have noticed that certain HTML mail take several
> seconds before preview (or open). During the "lag" KMail basically
> freeze and my laptop fan runs amok. CPU hits 25% KMail on a i5 second
> gen Intel w 4 Gb RAM
>
> It is difficult to give examples as it is not all HTML but one is
> basically any from cnet.com (I subscribe to several newsletters).
>
> Has anyone else noticed this or is it unique to something in my
> setup/configuration.
>
> This is KDEPIM 4.13 with the baloo indexing
>
> Kind regards
> Sinclair
>
some comments after searching around a bit on forums:

some more details, after a bit experimenting:
If I switch off HTML "preference" in the security settings part all is 
smooth even when I then use the "show html by clicking here" function.

Also KMail/Kontact then use about 120 Mb RAM whereas with "HTML mail 
preferred" it quickly goes up to around 500 Mb and keeps growing.

So it does not seem to be the viewing itself but something connected to 
preferring to have HTML mail shown (without loading external preferences).

However, this makes some mail simply saying "go to this webpage" that 
kind of makes it a bit pointless to have them as mail and completely 
disturbs my workflow

seems to be bug 331156 in bugs.kde.org

/Sinclair