Disappearanced code of main.ts when editing custom.js

Describe the bug
Disappearanced code of main.ts when editing custom.js

To Reproduce
Steps to reproduce the behavior:

1. Create new project (name is 'test')
2. Change to editor as javascript
3. Open explorer, click '+', and create new custom.ts
4. Change to editor as javascript
5. Write following codes

basic.forever(function () {
custom.foo(5, "Hello", MyEnum.One)
})

6. Open custom.ts
7. Rename "foo" to "foo2"
8. Change to editor as javascript

Change "custom.foo(" to "custom.foo2("

9. Change to editor as blocks

Expected behavior
The blocks are displayed correctly

Screenshots

Added screenshots as Step7, 8, 9

micro:bit version (please complete the following information):

micro:bit v2.0, Interface Version: 0257

Desktop (please complete the following information):

• OS: Windows 10 Home 22H2 build 19045.2364
• Browser: Chrome 108.0.5359.100（Official Build）(64 bit)

Additional context

Start by reproducing the editor sequence in the issue: create custom.ts, define custom.foo, rename it to custom.foo2 in JavaScript, and switch back to blocks. Compare the displayed blocks with the expected code, paying attention to the main.ts and custom.js/custom.ts references. Done means the blocks remain correctly displayed after the rename.