vscode调试c程序提示Unable to perform this action because...怎么办？

Question

我用vscode+WSL来配c开发环境，照网上说的配好了launch.json和tasks.json，launch.json里externalConsole值为true，怎么不出现网上说的那种弹出调试框，而是仍然在下方的调试控制台输入输出？

launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "gcc - 生成和调试文件",
            "type": "cppdbg",
            "request": "launch",
            //编译完成的可执行文件
            "program": "/mnt/e/Code/CTest/${fileBasenameNoExtension}.o",
            //"args": ["-fThreading"],
            "args": [],
            "stopAtEntry": false,
            //项目所在目录
            "cwd": "/mnt/e/Code/CTest",
            "environment": [],
            "externalConsole": true,
            //调试时跳转到内部调试台
            //"internalConsoleOptions": "openOnSessionStart",
            //启动前的预执行任务要与tasks.json中label一致
            "preLaunchTask": "gcc 编译文件",
            "windows": {
                "MIMode": "gdb",
                "setupCommands": [
                    {
                        "description": "Enable pretty-printing for gdb",
                        "text": "-enable-pretty-printing",
                        "ignoreFailures": true
                    }
                ]
            },
            "pipeTransport": {
                "pipeCwd": "",
                "pipeProgram": "c:\\windows\\sysnative\\bash.exe",//通常不需要修改
                "pipeArgs": ["-c"],
                "debuggerPath": "/usr/bin/gdb"
            },
            "sourceFileMap": {
                "/mnt/e": "E:\\"//地址转换
            }
        }
    ]
}