Impossible to import a wallet

[TooManyDots]

Hi,

when I click the "Select Wallet File"-Button it opens a dialog to select a file, but the window in which the button was instantly closes. This makes it impossible to import my wallet.
To illustrate this:

1. https://i.imgur.com/V6Mn90N.png
2. https://i.imgur.com/4XJRtUF.png
3. https://i.imgur.com/u4jDw9c.png

Chrome: Version 67.0.3396.79 (Official Build) (64-bit)
WebExtensionWallet: 3b4b100
OS: Win7

[yupnano]

这个问题是操作系统的原因，参考这两个issue
#10
#4