Hi Raul,
Thanks for the update.
It appears that in the autocomplete popup there is additional space between the left margin and the items. But the indent behavior is same with lowercase and upper case characters . Please refer the attached screenshot in which indent behavior is same with autocomplete enabled combobox and standard combobox listing same set of items.
http://files.syncfusion.com/support/Tools.Windows/7.1.0.30/F80198/f80198_screesnhot1.zipPlease let me know if you want to reduce the space where the items starts in the popup.
Regards,
Jaya