This concerns InsetPreview, InsetIPA and InsetMathHull.
Caching such a value is bad when opening the same buffer in two views.
In this case, it is not necessary to remember use_preview_ at all,
actually.
Also remove private member dim_ which is not used and remove some trailing whitespace.
Fixes bugs #9085 abd #9957.
The rule-of-three says that if any of virtual destructor, copy constructor
or assignment operator needs to be manually implemented, then all three
should be implemented. Otherwise you can get subtle bugs which can be
difficult to find. In the changed classes, changing a copy-construction to
an assignment would have had surprising effects. Now they all behave
consistently.
preparatory to fixing #7080. Note that mathed uses the same routine, but
for a completely different purpose, so I did not rename it there. I have
seen no difference in behavior after testing, e.g., opening and
exporting Math.lyx, and also re-saving it and looking at the diff.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@38109 a592a061-630c-0410-9148-cb99ea01b6c8
