[SalesForce] Hide Flow buttons in salesforce

Do I have to change the j$().text to fit with a checkbox?

This is correct. I went and started to look at the HTML for checkbox and saw it is in fact an image that they are using. What I suggest is to read an attribute from that image such as alt or title as you can see how the HTML looks below

<div id="00N50000003JWbq_ileinner"> <img src="/img/checkbox_checked.gif" alt="Checked" width="21" height="16" class="checkImg" id="00N50000003JWbq_chkbox" title="Checked"> </div>

This would be the javascript I would have to use to get the value "Checked" as shown below:

j$("#00N50000003JWbq_chkbox").attr('title');

What I'm doing here in the javascript / jquery, is I find the section of html which is holding on the precious information I want to extract, and since it has a child record, I'm using the children() function to go a step deeper inside the html as this is nested within your div container. Lastly, I use the attr() method which allows me to call any attribute as seen above in the html image tag to retrieve a value.

Please remember to use the correct ID as this was an example from my side. Lastly, I would also recommend checking to see if your developer console / firebug / trouble shooting application tells you if you have any errors via javascript.

In init method you can do like this. Find the button by Id. Use aura:id

<ui:button label="New Milestone" press="{!c.newMilestone}" class="slds-button slds-button--brand" aura:id="newmilestonebutton" />

var newbutton = component.find('newmilestonebutton');
$A.util.removeClass(newbutton, 'uiButton--default uiButton');

Or do the same thing in afterRender() method in Renderer file. You have to override the afterRender() method.