wojtek wrote:Thank you for the explanation.
Maybe MetaQuotes could do something with that...
(and add thicker bars). 

I don't know.
The same way of handling objects exists in metatrader 5 too, so I don't think so
As an example of different handling of the same thing, here is the same thing in tradestation :

As you can see no such issue there and objects are handled exactly as they are expected to be handled (including the rectangle border line colors)