BUG: Third party input method initial letter malposition

Hi, Third party input method have a initial letter malposition problem.

I transcibe a gif, just like this


I want to input 'hao', but actually input the 'aoh', this bug seem initial element problem.

If not first line, this problem is not found, just like this


Start by reproducing the GIF in the Pell editor with a third-party input method, comparing input on the first line with input on later lines. Trace the initial-line input handling and verify that entering “hao” preserves that order on the first line without changing behavior elsewhere.

Written by the indexing model from the issue text.