Please help us help you and fill where relevant:
Your LimeSurvey version: 5.2.13
Own server or LimeSurvey hosting: Lime Survey
Survey theme/template: fruity
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When using the multiple-choce bootstrap button, a window always appears as with multiple selections through checkboxes. When selecting the single choice bootstrap button, the bootstrap buttons are displayed correctly. Could you pls. help me to reslove this issue? Thank you.

If hosted at LimeSurvey GmbH, you should contact their support directly.

Can you supply screenshots and a small sample survey (.lss file) containing only the relevant question.

+1 for screenshots,

> When using the multiple-choce bootstrap button, a window always appears as with multiple selections through checkboxes.

I realy don't understand …