Datacube target usage to open/close grouped sets of rows

[alucab]

Hello

I am experimenting with the Datacube for some visualizations where i need a tree based hierarchical view of my dataset and it fits really nicely

The only problem I had is the usage of the Target field, I really cannot wrap my mind around the usage and it seems there is no documentation

My objective is far similar to this post, to be able to programmatically control the opening of the tree

DataCube's target and collapsed parameters

I’d like my DataCube to startup with all rows expanded. I thought I’d be able to do this by setting the collapsed parameter of its grouping argument to False, but apparently that’s the default and it doesn’t have the desired effect. I was then looking into whether I could set the initial value of the target ColumnDataSource to accomplish this goal, but also no luck. See the (not so minimal) working example below, in which I put in a button to allow me to examine the current value of target, and…

At now I didn’t find any documentation neither sample on how to set the target parameter to open a grouped set from a callback or at the start

Thanks