adding select=attr_name in a symbol will select the text of attr_name value when editing attributes of a placed instance of the symbol. Specifying select=* will select all the text. If select attribute in symbol is not present try to select "value, lab, name" in this order, if found. Also select all text in text objects when editing their content.

doc/xschem_man/symbol_property_syntax.html

@@ -99,6 +99,9 @@ p{padding: 15px  30px 10px;}
 
  <li><kbd>template</kbd>: Specifies default values for symbol parameters</li>
 <img src="general_rules.png">
+
+ <li><kbd>select</kbd>: specify an attribute value (not the attribute name) to select when editing properties of
+     a placed instance of the symbol. Specifying <kbd>select=*</kbd> will select all the attribute text.</li>
  </ul>
  <p>
   The order these attributes appear in the property string is not important, 

src/xschem.tcl

@@ -5689,6 +5689,9 @@ proc enter_text {textlabel {preserve_disabled disabled}} {
     }
   }
   bind .dialog.txt <Shift-KeyRelease-Return> {return_release %W; .dialog.buttons.ok invoke}
+  .dialog.txt tag add sel 1.0 {end - 1 chars}
+  .dialog.txt mark set insert 1.0
+  focus .dialog.txt
   #grab set .dialog
   tkwait window .dialog
   return $retval
@@ -6514,21 +6517,27 @@ proc edit_prop {txtlabel} {
 
   tkwait visibility .dialog
   # select text after value= or lab= and place cursor just before selection
-  set regx {value *= *("([^"]|(\\"))+"|[^ \t\n"]+)} ;# vim syntax fix "
+
-  set regx1 {value *= *[^ \n]}
+  set sym_sel_attr [xschem getprop symbol $symbol select]
-  set idx [.dialog.symprop search -regexp -nolinestop -count nchars $regx 1.0]
+  if {$sym_sel_attr eq {*}} {
-  .dialog.symprop search -regexp -nolinestop -count len $regx1 1.0
+     .dialog.symprop tag add sel 1.0 {end - 1 chars}
-  incr len -1
+     .dialog.symprop mark set insert 1.0
-  if {$idx eq {} } { 
+  } else {
-    set regx {lab *= *("([^"]|(\\"))+"|[^ \t\n"]+)} ;# vim syntax fix "
+    foreach attr [list $sym_sel_attr value lab name] {
-    set regx1 {lab *= *[^ \n]}
+      if {$attr eq {}} {continue}
-    set idx [.dialog.symprop search -regexp -nolinestop -count nchars $regx 1.0]
+      set regx {}
-    .dialog.symprop search -regexp -nolinestop -count len $regx1 1.0
+      set regx1 {} 
-    incr len -1
+      append regx $attr { *= *("([^"]|(\\"))+"|[^ \t\n"]+)} ;# vim syntax fix "
-  }
+      append regx1 $attr { *= *[^ \n]}
-  if { $idx ne {} } {
+      set idx [.dialog.symprop search -regexp -nolinestop -count nchars $regx 1.0]
-    .dialog.symprop tag add sel "$idx + $len chars" "$idx + $nchars chars"
+      .dialog.symprop search -regexp -nolinestop -count len $regx1 1.0
-    .dialog.symprop mark set insert "$idx + $len chars"
+      incr len -1
+      if {$idx ne {}} break
+    }
+    if { $idx ne {} } {
+      .dialog.symprop tag add sel "$idx + $len chars" "$idx + $nchars chars"
+      .dialog.symprop mark set insert "$idx + $len chars"
+    }
   } 
   focus .dialog.symprop
   tkwait window .dialog

xschem_library/ngspice/comp_ngspice.sym

@@ -1,4 +1,4 @@
-v {xschem version=3.4.5 file_version=1.2
+v {xschem version=3.4.8RC file_version=1.3
 *
 * This file is part of XSCHEM,
 * a schematic capture and Spice/Vhdl/Verilog netlisting tool for circuit
@@ -23,9 +23,10 @@ G {}
 K {type=subcircuit
 format="@name @pinlist @symname OFFSET=@OFFSET AMPLITUDE=@AMPLITUDE GAIN=@GAIN ROUT=@ROUT COUT=@COUT"
 template="name=x1 OFFSET=0 AMPLITUDE=5 GAIN=100 ROUT=1000 COUT=1p"
-}
+select=GAIN}
 V {}
 S {}
+F {}
 E {}
 L 4 -40 -50 -40 50 {}
 L 4 -60 -30 -40 -30 {}

xschem_library/ngspice/solar_panel.sch

@@ -1,4 +1,4 @@
-v {xschem version=3.4.6 file_version=1.2
+v {xschem version=3.4.8RC file_version=1.3
 *
 * This file is part of XSCHEM,
 * a schematic capture and Spice/Vhdl/Verilog netlisting tool for circuit
@@ -25,6 +25,7 @@ G {}
 K {}
 V {}
 S {}
+F {}
 E {}
 L 2 95 -1105 95 -875 {}
 L 2 135 -1105 135 -875 {}
@@ -431,12 +432,12 @@ lab=TRIANG }
 C {vsource.sym} 550 -790 0 0 {name=Vref value=7}
 C {lab_pin.sym} 550 -760 0 0 {name=l17  lab=0 }
 C {lab_pin.sym} 760 -720 0 0 {name=l13  lab=CTRL1 }
-C {comp_ngspice.sym} 660 -890 0 0 {name=x3 OFFSET=0.5 AMPLITUDE=1 ROUT=7k COUT=1n}
+C {comp_ngspice.sym} 660 -890 0 0 {name=x3 GAIN=100 OFFSET=0.5 AMPLITUDE=1 ROUT=7k COUT=1n}
 C {lab_pin.sym} 550 -860 0 0 {name=l16
 lab=REF}
 C {lab_pin.sym} 550 -920 0 0 {name=l15  lab=LED}
 C {lab_pin.sym} 830 -890 0 1 {name=l18  lab=LEVEL}
-C {comp_ngspice.sym} 950 -1000 0 0 {name=x4 OFFSET=0.5 AMPLITUDE=1 ROUT=1 COUT=1p}
+C {comp_ngspice.sym} 950 -1000 0 0 {name=x4 GAIN=100 OFFSET=0.5 AMPLITUDE=1 ROUT=1 COUT=1p}
 C {lab_pin.sym} 1060 -1000 0 1 {name=l19  lab=CTRL1 }
 C {lab_pin.sym} 160 -450 0 0 {name=l20  lab=SUN }
 C {spice_probe.sym} 850 -1030 0 1 {name=p4 analysis=tran}