Merging Indicators MT4

Hello, everyone I am currently trying to merge two indicators in one window. I was successful with merging the RSI and MFI together, but when I went to add the MACD’s together they would not merge, but I was able to place both in separate windows. The settings for the First MACD was (12,26,1), the second which is not shown in the picture is (5,15,1). I am clueless as to what could be preventing from doing this. If anyone can shed some light into this I would be very grateful. Thank You !

As i know if you want to merge more than one indicators just drag and drop them.

Yes I know I that it just seems that some indicators will merge like RSI and the MFI(Money Flow Index), so I’m puzzled as to why I can’t merge two MACD with different settings?