There is a problem copying with the tmux mouse function in the windterm

**Dear developer**,

I don't know if this is a bug. But I did find a problem.
In the `windterm2.5.0`, use `tmux3.3`, `set -g mouse on` to turn on the mouse function. Press `shift` and drag the left mouse button to select text. However, this function is not available in the windterm. It is no problem to do with `xshell7`.
**Is this a bug in windterm?**

### 简体中文(Simplified Chinese)
如题，我不知道这算不算一个bug，但是我确实在使用中发现了一个问题。
在`windterm2.5.0`中，服务器使用`tmux3.3`以终端复用，使用`set -g mouse on`设置打开鼠标功能。按住`Shift`键和拖拽鼠标左键可以选取文本。然而我在`windterm`下发现此操作无效，文本无法被选取。之后换成`xshell7`尝试，功能是正常的。所以我不清楚这算不算是windterm的一个bug？我不知道其中的奥秘。我原本打算用`windterm`代替`xshell7`，但现在看来好像还不行。

The report names WindTerm 2.5.0, tmux 3.3, and the Shift-drag selection path, but no source file or test. First reproduce the behavior with mouse mode enabled and compare it with the described Xshell result; done requires a confirmed diagnosis and a project-specific fix or documented limitation.

Written by the indexing model from the issue text.