"however some of the IC's set the VCC pin to 5V netflag, while some of them to VCC netflag." I do not understand this. In simulation until recently, EasyEDA tried to automatically assign VCC and 5V voltage sources but this was almost impossible to get right so, AFAIK, since V6.4.19.3, this has been replaced by warnings to add supply voltage sources. However this only affected simulation schematics and the placement and naming of netflags to invoke these automatically added voltage sources was under user control. If you are creating non-simulation schematics then it is up to the user to place and name all nets, netlabels and netflags. EasyEDA does not automatically add or assign them. Can you make a public copy of a project that illustrates this problem and post the url to it here?