Fix height of resizer in exercise demo
Fix height of resizer in exercise demo

alpheios-project/arethusa,fbaumgardt/arethusa,latin-language-toolkit/arethusa,fbaumgardt/arethusa,fbaumgardt/arethusa,PonteIneptique/arethusa,Masoumeh/arethusa,alpheios-project/arethusa,Masoumeh/arethusa,alpheios-project/arethusa,PonteIneptique/arethusa,latin-language-toolkit/arethusa