Looks like it’s only searching in installed packages regardless of the highlighted tab on the left.
Try clicking on the green highlighted > in the lower left corner to complete the previously started action.
You can’t install software if there is update to perform, because package manager at first is checking mirror servers for new packages while “refreshing database”, then it performs system updates. After this you can install whatever you want. This is how it works on Arch Linux and Arch based systems in long story short.