In Sitemap and items defined groups are empty

Hello everyone,
im all new to Openhab still, but i am reading a lot of the documentation and am stuck now.
What i did so far is add my things through Paper UI (NOT in an configuration file) and create an item file and a sitemap file. I try to have my house´s floors in this sitemap as well as a group to show battery levels of my MAX Things, so i fille the sitemap file with the following code:

sitemap Standard label="Zuhause"
{
	Frame label="Gruppen"	
	{
		Group item=gBatteries label="Batteriestatus" icon=battery
		Group item=gattic label="Dachboden" icon=attic
		Group item=gfirstfloor label="Obergeschoss" icon=firstfloor
		Group item=ggroundfloor label="Erdgeschoss" icon=groundfloor
		Group item=gcellar label="Keller" icon=cellar
	}

}

In the items file i defined all my groups and, as i am just about to start, for testing purpose some devices. So heres my items entry:

//**********

//*** Places
		group gattic "Dachboden gesamt" <attic>
			group gDG "Dachgeschoss" <attic> (gattic)
				group gAZR "Arbeitszimmer R" <office> (gDG)
				group gAZL "Arbeitszimmer L" <office> (gDG)
				group gFloor "DG Flur" <corridor> (gDG)
			group gDG_Bad "DG Bad" <bath> (gattic)
		group gfirstfloor "Obergeschoss"
			group gOG_Kinderzimmer_links "Kinderzimmer L" <baby_2> (gfirstfloor)
			group gOG_Kinderzimmer_rechts "Kinderzimmer R" <boy_1> (gfirstfloor)
			group gOG_Schlafzimmer "Schlafzimmer" <bedroom> (gfirstfloor)
			group gOG_Bad "OG Bad" <bath> (gfirstfloor)
		group ggroundfloor "Erdgeschoss gesamt" <groundfloor> 
			group gEG "Erdgeschoss" <groundfloor> (ggroundfloor)
		group gcellar "Keller gesamt" <cellar> 
			group gK "Keller" <cellar> (gcellar)
		group gGarden "Garten" <garden> 
			group gGarten_hinten "Garten hinten" <garden> (gGarden) 
			group gGarten_vorne "Garten vorne" <garden> (gGarden)

//*** Funktionen

group gBatteries "Batteriestatus" <batterylevel> 
group gFensterkontakte "Fensterkontakte" <contact> 
group gThermostate "Thermostate" <temperature> 
group gWandthermostate "Wandthermostate" <temperature> 
 

//**********

//*** Batteriestatus
Switch Fensterkontakt_DG_Bad_Bat "Fensterkontakt DG Bad" (gBatteries,gDG_Bad) {channel="max:shuttercontact:MKF0061363:NEQ0165338:battery_low"}

//*** Fensterkontakte
Contact Fensterkontakt_DG_Bad_CON "Fensterkontakt DG Bad" (gDG_Bad) {channel="max:shuttercontact:MKF0061363:NEQ0165338:contact_state"}

//*** Thermostate

//*** Wandthermostate
Switch battery_WT_D "Batteriestatus Wandthermostat Dach" (gDG,gBatteries,gWandthermostate) {channel="max:wallthermostat:MKF0061363:NEQ0084458:battery_low"}
String Mode_WT_D "Thermostat Mode" (gDG,gWandthermostate) {channel="max:wallthermostat:MKF0061363:NEQ0084458:mode"}
Number Actual_WT_D  "Temperatur Dachgeschoss  [%.1f °C]" (gDG,gWandthermostate) {channel="max:wallthermostat:MKF0061363:NEQ0084458:actual_temp"}
Number SetTemp_WT_D "Zieltemperatur Dachgeschoss[%.1f °C]" (gDG,gWandthermostate) {channel="max:wallthermostat:MKF0061363:NEQ0084458:set_temp"}

My problem is, that in Basic UI i got all groups defined in sitemap showing up correctly, but when entering them, nothing is in there. Form my understanding of groups so far, when i open the “gattic” group labeled “Dachboden” i should see all corresponding groups under it, so group “gDG” and “gDG_Bad” with my shutter contact “Fensterkontakt” inside… but it doesnt. Same goes for battery level group which is completely empty, although i defined the groups…

I am grateful for help…

ohhhhhhhhh boy… for everyone having the same problem: Noob mistake:

Replace “group” with “Group” and mind the case sensitivity…