🚀 go-pugleaf

After lots more play, it works well. A similar method can be used
for selecting factories, to significantly reduce the number of
commands needed to work with factories (a single factory or all
factories of that type within view). 

... double-click 

... assign to group 7 or clear group 7 (if nothing is under the
pointer) 

... select the nearest factory 

... recall group 7, if any 

To select the nearest factory, hover the pointer over an open
space. 

To select all factories (within view) of that type, hover the
pointer over a factory. 

If the pointer is over an open space... The group number 7 is 
cleared. After the nearest factory is selected, recalling group 7
does nothing. 

If the pointer is over a factory... The double-click selects all
of those factories within view and they are assigned to group 7.
Then, after the nearest factory is selected (the factory under the
pointer since it is the nearest factory), recalling group 7
selects the entire group again. 

The code looks like this.

    Mouse("left:2/5")+
    Key("c-7/5")+
    Key("h/5")+
    Key("7/5")+