Bug: Shadow is shown on inactive pane when enabling Dual Pane mode

### Description

The shadow is initially shown on the inactive pane when enabling Dual Pane mode.

### Steps To Reproduce

1. Enable dual pane mode
2. Notice how the shadow is active on the wrong pane

### Requirements

- Correctly switch shadow to the new pane

### Files Version

v3.4.2

### Windows Version

Windows 11

### Log File

NA