@chmedly said:

If I type 1.25/2 in the box I get a circle with a radius of 1.25. I've tried a number of different ways of typing this to no avail.

So try 125/200 instead of 1.25/2 .
See https://www.youtube.com/watch?v=crY8SVypzMQ

Density could help in case of static objects, because more dense object behaves as harder one. But density changes also mass and inertia. So in case of chain, I have tested density of chain links from 0.01 to 100 and the result is almost identical :

http://staff.cesnet.cz/~michal/vms/original/Chain_test_SketchyPhysics.skp

Only once helped when I renamend for a while the ControlPanel.html, and after some errors and crashes SP started open the rest .html in SP windows. Then I renamed ControlPanel.html back. But now the problem persists

Without lengthy explanation, see the short video (7sec):
[flash=648,480:2h8htwl7]https://www.youtube.com/v/FZKWZ1w8n0M[/flash:2h8htwl7]
Is there any way how to avoid this behaviour of SketchyPhysics objects?
It seems to me that this is the essential problem which substantially degrade usability of the SketchyPhysics plugin.
SketchyPhysics_solid_problem_demonstrator.skp

Hi,
for reason unknown, SketchyPhysics started to open its ControlPanel.html, UpdateDialog.html, Inspector.html, UpdateDialog.html etc. in browser. What the hell happened? How to avoid it?