PerspectiveWidget gets in unrecoverable state

[robambalu]

Reproduce the issue:

• create a multi-line d3_y_line graph
• go to the edit settings, change view to datagrid
• go back to y-line

at this point the graph will only show 1 of the lines, and going into edit wont let you choose multi lines again either ( seems to be in an unrecoverable state at this point )

sample graph:
import pandas
x = pandas.DataFrame( { "a" : list(range(10)), "b" : list(x*x for x in range(10))})
perspective.PerspectiveWidget( x, plugin='d3_y_line')

after going through3 steps above:

[texodus]

Use shift+click on the inactive columns to additional columns when in chart mode, or drag/drop them from bottom to top (this is just the reverse of the behavior of click and shift+click in Datagrid mode).

There is a bug here in PerspectiveWidget though - setting plugin to "d3_y_line" without also explicitly setting columns should not default to all columns (as it does currently), but rather should display the behavior shown in your screenshot, e.g. choose a single numeric column if one is not already in the 1st position of the column selector. To get the chart you want, the (intended) API would be:

import pandas
x = pandas.DataFrame( { "a" : list(range(10)), "b" : list(x*x for x in range(10))})
perspective.PerspectiveWidget( x, plugin='d3_y_line', columns=["a", "b", "index"])

[robambalu]

I see, ctrl+shift does seem to let me add them back in, but its odd to see it drop them all by switching to datagrid and then back ( also, I may be missing it, but why the need for ctrl+?)

[texodus]

I suspect this would be more obvious on a non-trivial example with more than 3 numeric columns, e.g. Superstore example has 21 columns, only 5 of which are numeric and only 2 of those share a logic axis. Perspective will not change arguments supplied explicitly as kwargs but fills in other parameters with sane defaults to prevent overdraw, and will modify parameters using these defaults when the context changes due to user interaction.

Shift+ (not Ctrl+) just toggles the default behavior - in Chart mode it makes the UI act like a DataGrid, and vice-versa. Drag/drop works the same in both modes.

[robambalu]

understood, thanks Andrew