fix: Fixed bug with new panels not always showing initial content

[bmingles]

DH-18347: Fixed bug with new panels not always showing initial content

Test Cases

Using the script:

from deephaven import time_table

t1 = time_table("PT2S")

t2 = time_table("PT2S")

t3 = time_table("PT2S")

Case 1

• Close all panels except the one containing the script. Run the entire script
• A new tab group should open containing 3 panels
• The active panel should be t3
• Clicking on t2 or t1 should load it for the first time
• Clicking off a loaded panel and back should not reload

Case 2

• Close all panels except the one containing the script. Run the entire script
• Close panels t1 and t2
• Rerun entire script
• t1 and t2 should re-open to the right of t3
• t3 panel should refresh and remain the active panel
• Clicking on t1 or t2 should load it the first time
• Clicking off and back should not reload

Case 3

• Close all panels except the one containing the script. Run the entire script
• Drag t1 into a new tab group
• It should load its content
• Rerun entire script
• All panels should remain in current tab groups
• t1 and t3 should reload
• t2 should not load until you click on it to make it visible

Case 4

• Close all panels except the one containing the script. Run the entire script
• Drag t3 to a new tab group
• t2 should load its content as it becomes the active tab in the first tab group

Case 5

• Close all panels except the one containing the script. Run the entire script
• In the Panels treeview, click t3
• t3 should refresh
• click t1
• t1 should become active and refresh
• close t1
• click on t1 in the Panels treeview
• t1 should re-open in the tab group

[github-actions]

End-to-end Test Summary

Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Pending ⏳	Other ❓	Flaky 🍂	Duration ⏱️
6	6	0	0	0	0	0	04:52:52

A ctrf plugin

Detailed Test Results

Name	Status	ms	Flaky 🍂
should default to the correct settings	passed ✅	1977
should return custom settings: Empty configs	passed ✅	281
should return custom settings: Populated configs	passed ✅	100
should be able to load VSCode	passed ✅	1052
should only be visible when a supported file type is active: test.groovy	passed ✅	2655
should only be visible when a supported file type is active: test.py	passed ✅	1076

A ctrf plugin

Failed Test Summary

No failed tests ✨

Flaky Test Summary

No flaky tests detected. ✨

[mofojed]

This logic is missing the case where the newly created panel is not the initially active panel but it is already visible:

This can happen with the example you provided.
Steps to Reproduce:

1. Run the snippet creating t1 and t2
2. Move both panels to a separate tab stack than the code
3. Close t1
4. Run the code snippet again

Expected Results
4. t2 should refresh in the location it's in, t1 should open up and load if visible

Actual Results
4. t2 becomes active but t1 shows up as a blank panel. Once selected it becomes visible.

I think there's a follow up here as well, since what I really expect is all the panels to open in the same stack. It's weird/annoying to have the panel open up in the same stack as the code, since now my Editor is blocked. I'd rather it would open all the panels in a new stack on the first run, and on subsequent runs open in the same panel if they already exist, or the same stack as one of the panels that already exists.