When right clicking on an object to get the popup/context menu for that object, it just closes after ~1 second in some cases, e.g. when object is below horizon. Tested on Fedora 28 with Qt 5.10.1 and KF5 5.48, also known on Arch Linux and Fedora Rawhide (Qt 5.11.1 and KF5 5.48). To reproduce you can use a current Fedora Rawhide Astronomy live build (https://koji.fedoraproject.org/koji/taskinfo?taskID=28714105), just start KStars and right click on object below horizon. Further investigation shows that this has been introduced with https://cgit.kde.org/kstars.git/commit/?id=a852d0c6edced5263a00361368222e8f3ed96eba
Using reverted patch for Fedora downstream packaging until we have better solution: https://src.fedoraproject.org/rpms/kstars/blob/master/f/kstars-undo-a852d0c6edced5263a00361368222e8f3ed96eba.patch
Can be reproduced on Kubuntu 18.04 using INDI/KStars Nightly as in http://indilib.org/download/ubuntu.html Screen record: https://lupinix.fedorapeople.org/kstars-popup-bug.webm