CGContextSetFillColorWithColor: invalid context 0x0

[wuzer]

xcode 8.2.1 control output CGContextSetFillColorWithColor: invalid context 0x0. Backtrace: <-[SWFrameButton sw_backgroundImage]+420> <-[SWFrameButton layoutSubviews]+128> <<redacted>+1196> <<redacted>+148> <<redacted>+292> <<redacted>+1016> <<redacted>+72> <-[SWFrameButton setSelected:]+1168> <-[SWFrameButton commonSetup]+896> <-[SWFrameButton initWithFrame:]+192> <<redacted>+684> <-[GrabListTopView getCornerButton:]+76> <-[GrabListTopView setupSubviews]+108> <-[GrabBaseView initWithFrame:]+168> <-[GrabListViewCell setupSubviews]+512> <-[JFBaseTableViewCell initWithStyle:reuseIdentifier:]+176> <<redacted>+540> <<redacted>+88> <-[GrapViewController tableView:cellForRowAtIndexPath:]+116> <<redacted>+716> <<redacted>+80> <<redacted>+2304> <<redacted>+116> <<redacted>+176> <<redacted>+1196> <<redacted>+148> <<redacted>+292> <<redacted>+32> <<redacted>+252> <<redacted>+512> <<redacted>+120> <<redacted>+32> <<redacted>+372> <<redacted>+1024> <CFRunLoopRunSpecific+444> <GSEventRunModal+180> <<redacted>+684> <UIApplicationMain+208> <main+124>