Split action remains disabled for a second tab after splitting another tab

[v-xianya]

Storage Explorer Version

1.45.0-preview.1

Regression From

1.44.0

Architecture

x64

Storage Explorer Build Number

20260727.1

Platform

All

OS Version

Windows 11 arm64/Windows 11 x64/MacOS Tahoe 26.4.3 /Linux Ubuntu 22.04

Bug Description

When two different explorer tabs are open, splitting the first tab causes the Split action to become disabled not only for the already split tab, but also for the second tab. As a result, the second tab cannot be split independently.

Resource Types

No response

Authentication Method

None

Connection Type

None

Steps to Reproduce

1. Launch Storage Explorer.
2. Open two different explorer tabs (Tab 1 and Tab 2).
3. Right-click Tab 1 and select Split.
4. Verify that Tab 1 is successfully split.
5. Right-click Tab 2.
6. Observe the state of the Split action in the context menu.

Actual Experience

The Split action is disabled for Tab 2 after Tab 1 has been split.

Expected Experience

The Split action should remain enabled for Tab 2 if it has not been split yet.

Additional Context

This issue may have been introduced by the fix for the bug 9128.

[craxal]

Root cause: In TabPanelViewModel.openTabContextMenu (src/Standalone), the fix for #9128 added a guard requiring the shared split panel to contain exactly one tab panel before the Split action is enabled. Because that split panel is shared across tabs, once any tab is split the guard evaluates false for every tab -- disabling Split even on a second, un-split tab. That is the regression reported here.

Fix: Reverted ADO PR !757278 in its entirety, restoring the original condition so Split availability depends only on whether the tab can be cloned, and removing the unit test that PR added. This returns the Split action to its pre-#9128 behavior; a second un-split tab can be split again.

Draft PR (ADO): https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_git/StorageExplorer/pullrequest/763742