Variable viewer does not show any variables and error popps up

Just got the error:

Failed to load variables infojava.lang.RuntimeException: Request was discarded

The variable viewer didn’t display any variables. I guess this is related to the error message. After some clicks here and there it was working again, but display of the variables is still extremely slow.

This might be related to the reactive mode: the whole notebook is executed when I run a cell. During execution the variables are not shown.

I think this is not directly related: Variable viewer not showing things - #4 by William_Xu