Scratch-gui: Alert message div blocked some menu bar dropdown buttons

[JinXJinX]

Expected Behavior

Alert message should not block partial menu bar dropdown buttons.

Actual Behavior

menu bar dropdown buttons are blocked by alert message div

Steps to Reproduce

1. trigger a alert message
2. click 'file' button in menu bar
3. you can see 'new' button and 'load from computer' button is covered by alert's div

_Explain what someone needs to do in order to see what's described in Actual behavior above_

Operating System and Browser

Mac OS 10.14.2 Safari 12.0.2/ Chrome 71.0.3578/ FireFox 64.0.2

[thisandagain]

@carljbowman Any thoughts on the desired z-index here? I can see arguments both ways.

[carljbowman]

Seeing this, I lean towards z-indexing the nav and nav menus above alerts. Since alerts sometimes prompt using the file menu: for example if you lose an internet connection we prompt you to download your project. We do provide a download button in this specific alert example, but I could see people attempting to use the File > Menu to try to reinitiate a save or download to computer.

It's also a bit awkward that alerts could potentially block "Undo" & "Redo" in the Edit menu.

All that said, I am open to other thoughts as to why we should keep the current z-indexing or alerts above nav and nav menus.

[thisandagain]

Thanks @carljbowman. Sounds good.

[thisandagain]

/cc @chrisgarrity Another z-index issue if you'd like to add this one to your backlog.

[benjiwheeler]

Related to https://github.com/LLK/scratch-gui/issues/4226

[benjiwheeler]

From my checking, it appears this issue was already fixed before #4916 went in. Possibly it was fixed by #4452.

[apple502j]

@benjiwheeler Not for me on Firefox 76:
1) On sound tab, upload non-sounds (this creates an alert that cannot disappear)
2) You cannot click Code/Costume tab
3) On develop you can

[benjiwheeler]

@apple502j I totally agree about the Code/Costume tabs. But this issue is about menu bar dropdown menus.