Installing SynEdit gives errors

I have been trying to install SynEdit for the last two weeks but no luck. i downloaded its latest version, (I have Delphi XE2), extracted it, went to the packages folder, opened DelphiXE2.groupproj. Delphi IDE started, in the project manager, I right clicked SynEdit_RXE2.bpl and build it (succesful).

Then build SynEdit_DXE2.bpl but this time it gave error. This is it:

For this line:

{$IMPLICITBUILD ON}

It says

[DCC Fatal Error] SynEdit_RXE2.dpk(30): E2225 Never-build package 'designide' must be recompiled

And below this it says:

[DCC Fatal Error] SynEdit_DXE2.dpk(35): E2202 Required package 'SynEdit_RXE2' not found

Please tell me how to install it correctly.

Follow these instructions:

1. Clone the github repo: https://github.com/SynEdit/SynEdit
2. Open the XE2 group project in Packages\DelphiXE2.groupproj.
3. Add SynHighlighterJSON to SynEdit_DXE2. It is used by SynEdit_RXE2 and is, as I write this answer, missing from SynEdit_DXE2.
4. Build both projects in the project group, for instance by using Project | Build All Projects.
5. Install the design time package SynEdit_DXE2.

Since the project did not build without modifications, I suspect that the testing on older Delphi versions is not as comprehensive as it should be. However, I have just followed the steps above, and successfully installed the library.