The pager renders the pages before and after the open one, and each
fetched its message and conversation and mounted its own WebView at the
same time as the message the user had tapped, which competed with it
for the network, the JS thread and the WebView process.
The neighbouring pages now show their header and placeholder lines
until the open message's body has reported its height, the user starts
to swipe, or 1.5 s have passed. Their details are then loaded together
in one request, and their conversations and WebViews follow.
Linus Rath
01fc6fbba5