XPages: checkbox (groups) looses their value(s) when changing to edit mode - xpages

Question

Crazy effect: I open a (previously saved) doc in read mode: Everthing is ok. When I change it into edit mode: All checkboxes are emptied. The other items (inputText, inputTextarea) on the xpage keep their values.
The effect doesn¨t occur when I open the page for the first time (of my browser session), but after that it happens every time.
code snippet:
<xp:panel id="pNewDoc" styleClass="panel panel-default">
<xp:this.data>
<xp:dominoDocument var="dshare" formName="dshare"
action="openDocument"
databaseName="webapp/peoplesearch/dshare.nsf">
<xp:this.documentId><![CDATA[#{javascript:viewScope.myUnid}]]></xp:this.documentId>
</xp:dominoDocument>
</xp:this.data>
<xp:this.rendered><![CDATA[#{javascript:viewScope.ShowDoc == "1"}]]></xp:this.rendered>
<div class="panel-heading">
<xp:label value="Desk Sharing Freigabe" id="label7"
for="inputText1" styleClass="panel-title">
</xp:label>
</div>
<xp:div styleClass="panel-body">
<div class="row hvrow">
<xp:label value="Owner" id="label2"
styleClass="col-sm-2 col-md-2">
</xp:label>
<xp:div styleClass="col-sm-4 col-md-4">
<xp:inputText id="inputText4"
value="#{dshare.anOwner}"
defaultValue="#{javascript:#UserName()}" disabled="true">
</xp:inputText>
</xp:div>
<xp:label value="Tel." id="label6"
styleClass="col-sm-2 col-md-2">
</xp:label>
<xp:div styleClass="col-sm-4 col-md-4">
<xp:inputText id="inputText5"
value="#{dshare.dsPhoneNumber}">
<xp:this.defaultValue><![CDATA[#{javascript:var
dbArray = [""];
dbArray.push("webapp/peoplesearch/psuser_20160610.nsf")
#DbLookup(dbArray,"lookupFullname",#UserName(),"OfficePhone")}]]></xp:this.defaultValue>
</xp:inputText>
</xp:div>
</div>
<div class="row">
<xp:label value="Von bis" id="label1"
styleClass="col-sm-2 col-md-2">
</xp:label>
<xp:div
styleClass="col-sm-4 col-md-4 form-inline">
<xp:inputText id="inputText1"
value="#{dshare.dsFrom}" style="width:45%">
<xp:dateTimeHelper id="dateTimeHelper3">
</xp:dateTimeHelper>
<xp:this.converter>
<xp:convertDateTime type="date"
dateStyle="short">
</xp:convertDateTime>
</xp:this.converter>
</xp:inputText>
 - 
<xp:inputText id="inputText2"
value="#{dshare.dsTo}" style="width:45%">
<xp:dateTimeHelper id="dateTimeHelper4">
</xp:dateTimeHelper>
<xp:this.converter>
<xp:convertDateTime type="date"
dateStyle="short">
</xp:convertDateTime>
</xp:this.converter>
</xp:inputText>
</xp:div>
<xp:label value="Zeitspanne" id="label3"
styleClass="col-sm-2 col-md-2">
</xp:label>
<xp:div styleClass="col-sm-4 col-md-4">
<xp:checkBoxGroup id="checkBoxGroup1"
value="#{dshare.dsPeriod}">
<xp:selectItem itemLabel="Vormittag"
itemValue="V">
</xp:selectItem>
<xp:selectItem itemLabel="Nachmittag"
itemValue="N">
</xp:selectItem>
</xp:checkBoxGroup>
</xp:div>
</div>
<div class="row">
<xp:label value="Details" id="label9"
styleClass="col-sm-2 col-md-2">
</xp:label>
<xp:div styleClass="col-sm-10 col-md-10">
<xp:inputTextarea id="inputTextarea1"
style="width:100%" rows="5" value="#{dshare.dsDetails}">
</xp:inputTextarea>
</xp:div>
<xp:label value="Status" id="label10"
styleClass="col-sm-2 col-md-2">
</xp:label>
<xp:div styleClass="col-sm-4 col-md-4">
<xp:checkBox text="aktiv" id="checkBox1"
value="#{dshare.dsStatus}" checkedValue="activ"
uncheckedValue="inactiv" defaultChecked="true">
</xp:checkBox>
</xp:div>
</div>
</xp:div>
<div class="panel-footer" style="text-align:right">
<xp:button value="Bearbeiten" id="btEdit" type="submit"
rendered="#{javascript:!dshare.isEditable()}">
<xp:eventHandler event="onclick" submit="true"
refreshMode="partial" immediate="false" save="false"
refreshId="pNewDoc" execMode="partial" execId="pNewDoc">
<xp:this.action>
<xp:changeDocumentMode mode="edit"></xp:changeDocumentMode>
</xp:this.action>
</xp:eventHandler>
</xp:button>
<xp:button value="Speichern" id="btSave" type="submit"
rendered="#{javascript:dshare.isEditable()}">
<xp:eventHandler event="onclick" submit="true"
refreshMode="partial" immediate="false" save="false"
refreshId="pDSall" execMode="partial" execId="pDSall">
<xp:this.action><![CDATA[#{javascript:viewScope.ShowDoc = "0"
qsave(dshare);}]]></xp:this.action>
</xp:eventHandler>
</xp:button>
</div>
</xp:panel>

Answer 1

Your button has the property type="submit":
<xp:button
value="Bearbeiten"
id="button2"
type="submit"
rendered="#{javascript:!dshare.isEditable()}">
...
It is responsible for your issue.
Just delete type="submit" and your check boxes will work with setting edit mode by partial refresh:
<xp:button
value="Bearbeiten"
id="btEdit"
rendered="#{javascript:!dshare.isEditable()}">
<xp:eventHandler
event="onclick"
submit="true"
refreshMode="partial"
immediate="false"
save="false"
refreshId="pNewDoc"
execMode="partial"
execId="pNewDoc">
<xp:this.action>
<xp:changeDocumentMode mode="edit"></xp:changeDocumentMode>
</xp:this.action>
</xp:eventHandler>
</xp:button>