I dont know the right way to hide this fields, but you can delete it from tv form,
You should find file
assets\components\gallery\js\mgr\tv\galtv.js
This file contains TV form.
You should delete this:
,{
xtype: 'textfield'
,id: 'tv'+config.tv+'-gal_other'
,name: 'gal_other'
,fieldLabel: _('gallery.other_opt')
,description: _('gallery.other_opt_desc')
,value: config.data['gal_other'] || ''
,anchor: '97%'
,listeners: {'change':this.syncHidden,scope:this}
},{
xtype: 'fieldset'
,collapsible: true
,collapsed: true
,autoHeight: true
,title: _('gallery.watermark_options')
,items: [{
html: '<p>'+_('gallery.watermark_options_desc')+'</p>'
,border: false
},{
xtype: 'textfield'
,id: 'tv'+config.tv+'-gal_watermark-text'
,fieldLabel: _('gallery.watermark_text')
,description: _('gallery.watermark_text_desc')
,name: 'gal_watermark-text'
,allowBlank: true
,anchor: '97%'
,value: config.data['gal_watermark-text'] || ''
,listeners: {'change':this.syncHidden,scope:this}
},{
xtype: 'combo'
,id: 'tv'+config.tv+'-gal_watermark-text-position'
,fieldLabel: _('gallery.watermark_text_position')
,store: [
['BR',_('gallery.pos_br')]
,['BL',_('gallery.pos_bl')]
,['TR',_('gallery.pos_tr')]
,['TL',_('gallery.pos_tl')]
,['C',_('gallery.pos_c')]
,['R',_('gallery.pos_r')]
,['L',_('gallery.pos_l')]
,['T',_('gallery.pos_t')]
,['B',_('gallery.pos_b')]
]
,description: _('gallery.watermark_text_position_desc')
,name: 'gal_watermark-text-position'
,allowBlank: true
,anchor: '97%'
,typeAhead: false
,forceSelection: true
,triggerAction: 'all'
,selectOnFocus: true
,editable: false
,value: config.data['gal_watermark-text-position'] || ''
,listeners: {'select':this.syncHidden,scope:this}
}]
}
thanks.