These other options are greyed out because it's only for managing a HDD. To remove the Unallocated one,
open Run (Win key + R),
type "diskpart", hit Enter, click yes when prompted to run as Admin,
on Command Prompt, type "list disk" and hit Enter,
look for the correct disk number for SD card and that
matches with the Size of 32GB for first Partition, for example, the disk # is 2, so type "sel disk 2" and hit Enter,
type "clean" and hit Enter, this will wipe its all partitions off and merges back together.
Type "create partition primary" and hit Enter,
type "format fs=fat32 quick" and hit Enter,
type "assign letter=E" and hit Enter,
finally type "exit" and hit Enter to x out safely.
Now you got another 32GB back on your SD card. There was no need to use such third-party software to manage disk and partitions.