具體的操作步驟如下：
步驟一：打開Beyond Compare軟件，點擊上方的“工具”菜單，選擇“選項”命令
步驟二：左側選擇“啓動”欄目，右側勾選“在資源管理器環境菜單中包含Beyond Compare”，並在“比較”命令右邊位置點擊下拉按鈕，選擇主菜單
點擊確定就OK了。
測試：（注意：如果不好使請看最後）
選擇一個或多個文件可看到效果
如果還是不好使，可以參照官網解決辦法
https://www.scootersoftware.com/support.php?zz=kb_shellex
SHELL EXTENSION NOT DISPLAYED
If the shell extension is checked in the options dialog but it isn't displayed in Windows Explorer's right-click menu, applying registry patches will often fix the problem.
Beyond Compare 4 registry patch: BC4ShellExFix.zip
Beyond Compare 3 registry patch: BC3ShellExFix.zip
To apply the registry patches:
- Uninstall Beyond Compare.
- Download the registry patch zip file that matches your Beyond Compare version and unzip it.
- Double click on Remove.reg to remove Beyond Compare's shell extension registry entries.
- Reboot.
- Install Beyond Compare 3.3.13 or the current version of Beyond Compare 4.
- If Beyond Compare is installed to a location other than the default folder (C:\Program Files\Beyond Compare 4), edit the installation path in Add_64-bit.reg or Add_32-bit.reg.
- Double click on Add_64-bit.reg or Add_32-bit.reg to add Beyond Compare's shell extension registry entries. Use patch that matches the architecture (32-bit or 64-bit) of your operating system.
- Reboot.
翻譯過來就是：（但是並不需要這麼麻煩，直接執行步驟2，3，6應該就可以了）
- 卸載BCompare
- 下載對應BCxShellExFix.zip，並解壓
- 雙擊Remove.reg來移除BCompare的右鍵擴展功能菜單；
- 重啓電腦
- 重新安裝BCompare
- 根據電腦的位數選擇腳本：Add_32-bit.reg，Add_64-bit.reg。如果修改了BCompare的默認安裝路徑，則需要修改對應腳本中涉及到的BCompare路徑
- 再執行一次步驟6
- 重啓電腦