Comment 8 for bug 1950673

c:\CBH_Data\calibre.git>calibre-debug -w "path-to-book"
Turning on automatic hidpi scaling
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 86.46808510638297 x 86.41063122923588
Using calibre Qt style: True
[0.000] Load of book started
[0.000] prepared emitted
[0.015] webview loading requested
[0.218] bridge ready
[0.547] loading finished
***** This worked. I moved to the next chapter/file break then quit the viewer

c:\CBH_Data\calibre.git>calibre-debug -w "path-to-book"
Turning on automatic hidpi scaling
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 86.46808510638297 x 86.41063122923588
Using calibre Qt style: True
[0.000] Load of book started
[0.016] prepared emitted
[0.032] webview loading requested
[0.235] bridge ready
[0.563] loading finished
INFO: userscript:viewer.js:23: Ignoring unencrypted message from iframe: {"action":"ready"}
***** I see an empty screen
***** I quit the viewer by closing the window
INFO: userscript:viewer.js:23: Could not process message from parent:
INFO: userscript:viewer.js:16715: TypeError: Cannot read property 'decrypt' of undefined

c:\CBH_Data\calibre.git>calibre-debug -w "path-to-book"
Turning on automatic hidpi scaling
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 86.46808510638297 x 86.41063122923588
Using calibre Qt style: True
[0.000] Load of book started
[0.015] prepared emitted
[0.031] webview loading requested
[0.234] bridge ready
[0.547] loading finished
***** This worked