Collabora Office allows enter invalid filename. When someone attempts to type file name while creating document, which is too long or contains disallowed characters, the application does not show any warning and tries to create that file. The application get stuck on animation with a small rotating circle. However it does not freeze completely, because, the proces can be interrupted by pressing back button on system tray. The bug is not critical, but it can be annoying, because less experienced users may not know what is wrong and may think that the app does not work.

Steps to reproduce:

1) On the right bottom corner click on the + button,
2) select type of documents,
3) select directory,
4) type long or filename with disallowed characers (such as :!),
5) click on save button.

System information:

OS: Android
Device: Lenovo TB-7304F
App version: 6.4.3.