Problema 45091: a troca de idioma do teclado é interrompida com objetos chrome + flash diz:
it only happen at first time when user hold Shift key first then press Alt key once. if I hold on Alt and press Shift key, or try to press both keys at same time, this issue does not occur.
I have finally reproduced this issue today and investigated it. In brief, this issue is caused by our WindowWin class that consumes the first Shift+Alt key event (which raises a WM_SYSCOMMAND message) to set the menu focus to the wrench icon and does not dispatch it to the plugin.
Eu não sei se esse problema conhecido é aquele que você está encontrando, mas você pode tentar pressionar Alt antes de pressionar Shift.