Marking problem in Synaptic

[eager2no]

When I click into the tick box to mark something for installation, there is no tick mark.
The only way to install stuff is by right-clicking the item and selecting "Mark for install".

Item in Synaptic just after opening Synaptic:


Item in Synaptic once I click into the box:


Worked after install, went wrong some time later.

Anybody experienced this?
(running KDE on an MSI laptop)

TIA

[Texstar]

I am not able to duplicate. I can either click on the square box and mark for installation. I can double click on the entry and mark for installation or I can right click on the entry and mark it for installation. 

[Rudge]

When I click the item (highlight it that is) nothing happens except it becomes highlighted. When I click in the box, I get an options list that includes "mark for install" if I left click on either, I get the same list. At no point can I simply click on an item and have it marked for install.

[eager2no]

Texstar, Rudge,
Thank you for replying.
I don't know what got into that laptop. In addition to producing errors like this that nobody has ever heard of, I can't make it enter Options on boot. Pressing F2 will make it freeze. I have a good mind to trash it, although it is just 4 months old.