safari
I'm using a 2013 iMac 21.5 running Mojave and recently Safari has started causing two problems. It's Safari 12.0.2 and there has been a long-running problem with the sidebar, which when I open my homepage, stays on the homepage regardless of what sidebar sites are selected. The address bar at the top scrolls blue from left to right, and shows the title of the selected page, but the screen stays on the homepage. I can click on links all day, or enter web addresses, but the screen continues to show the same page no matter what. I have to close and reopen Safari before it all works properly. Sometimes it will just close to desktop and have to be reopened, but there is never a warning message or the old 'send report to Apple' window any more.
A second problem started last Sunday, when I was trying to book airline flights. I could select details on a page - flight, times etc - but when the box appeared to 'continue', I couldn't select the box. I was unable to select a link to move to the next stage, it was as if the mouse just wouldn't register on it. I closed Safari, started again, went back to the airline site, and the seats I had chosen were now greyed out, so their site was registering the selection, but Safari would not let me move on to the next page. After a very long time - where I booked about six seats on the same flight, but not one was able to be confirmed - I gave up and used another computer.
This morning on the Buy and Sell site 'Gumtree' I could not enter any text into the drop-down search box; all I got was the spinning wheel then crash to desktop. I closed Safari with great difficulty - the drop-down menu was not selectable - then it crashed again. I restarted again, and got two letters into the search box, before spinning wheel for about five minutes and then crash again.
I've restarted the Mac and have been able to access this site and post this ok, but I know it will start again after a while.
Any idea of a cause, or a cure?
iMac 21.5", 10.13