ngspice Simulator - Cannot create a different Simulation type for a simulated circuit

Description

Seem to be unable to create different types of simulations for the same circuit schematic. For example, the need is to enter a circuit schematic and then perform multiple simulation analyses, for example, a Transient simulation and then an AC simulation to examine circuit behaviour. I seem to be unable to do this and have been unable to find explanatory documentation to describe the process in KiCad 7.

Steps to reproduce

  1. Enter a circuit schematic for simulation
  2. Select 'Simulate circuit in SPICE' from toolbar
  3. In the Simulator window select 'Sim Command' and configure an initial AC simulation
  4. Hit Run/Stop Simulation button
  5. Add Signals with 'Add Signals' or 'Probe'
  6. Results are displayed in Simulation plot as expected
  7. Now I want to run a different simulation on the same circuit, say a Transient. It's not clear what the workflow is, so try 'New Plot' (File | New Plot)
  8. A new, blank 'Plot nn - AC' window appears.
  9. Try to change Simulation type by going to Sim Command button, clicking and selecting and configuring the Transient tab
  10. A new blank plot window, 'Plot nn - TRAN' appears
  11. Click 'Add Signals' (even though I suspect this is wrong thing to do), receive message 'You need to run plot-providing simulation first' - makes sense
  12. Click 'Run/Stop Simulation' button to try and generate new simulation
  13. A new, blank 'Plot nn - AC' window opens, focus removed from previous 'Plot nn - TRAN' window
  14. Click back to TRAN window, try to add signals, same message as before about 'run simulation first'.

So there is confusion about the proper workflow to achieve this, and the 'obvious' things to do seem not to work?

KiCad Version

Application: KiCad x64 on x64

Version: 7.0.5, release build

Libraries:
	wxWidgets 3.2.2
	FreeType 2.12.1
	HarfBuzz 6.0.0
	FontConfig 2.14.1
	libcurl/7.88.1-DEV Schannel zlib/1.2.13

Platform: Windows 10 (build 19045), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: May 27 2023 02:48:13
	wxWidgets: 3.2.2 (wchar_t,wx containers)
	Boost: 1.81.0
	OCC: 7.6.3
	Curl: 7.88.1-DEV
	ngspice: 40
	Compiler: Visual C++ 1936 without C++ ABI

Build settings:
	KICAD_SPICE=ON