Add "Tree view is always sorted by PID" option to mimic htop 2 behavior

Action.c

@@ -160,6 +160,9 @@ static bool collapseIntoParent(Panel* panel) {
 Htop_Reaction Action_setSortKey(Settings* settings, ProcessField sortKey) {
    settings->sortKey = sortKey;
    settings->direction = 1;
+   if (settings->treeViewAlwaysByPID) {
+      settings->treeView = false;
+   }
    return HTOP_REFRESH | HTOP_SAVE_SETTINGS | HTOP_UPDATE_PANELHDR | HTOP_KEEP_FOLLOWING;
 }
 

DisplayOptionsPanel.c

@@ -97,6 +97,7 @@ DisplayOptionsPanel* DisplayOptionsPanel_new(Settings* settings, ScreenManager*
 
    Panel_setHeader(super, "Display options");
    Panel_add(super, (Object*) CheckItem_newByRef("Tree view", &(settings->treeView)));
+   Panel_add(super, (Object*) CheckItem_newByRef("- Tree view is always sorted by PID (htop 2 behavior)", &(settings->treeViewAlwaysByPID)));
    Panel_add(super, (Object*) CheckItem_newByRef("Shadow other users' processes", &(settings->shadowOtherUsers)));
    Panel_add(super, (Object*) CheckItem_newByRef("Hide kernel threads", &(settings->hideKernelThreads)));
    Panel_add(super, (Object*) CheckItem_newByRef("Hide userland process threads", &(settings->hideUserlandThreads)));

MainPanel.c

@@ -25,7 +25,7 @@ static const char* const MainFunctions[]  = {"Help  ", "Setup ", "Search", "Filt
 
 void MainPanel_updateTreeFunctions(MainPanel* this, bool mode) {
    FunctionBar* bar = MainPanel_getFunctionBar(this);
-   FunctionBar_setLabel(bar, KEY_F(5), mode ? "Sorted" : "Tree  ");
+   FunctionBar_setLabel(bar, KEY_F(5), mode ? "List  " : "Tree  ");
 }
 
 void MainPanel_pidSearch(MainPanel* this, int ch) {
@@ -65,6 +65,9 @@ static HandlerResult MainPanel_eventHandler(Panel* super, int ch) {
       } else {
          reaction |= Action_setSortKey(settings, field);
       }
+      if (settings->treeViewAlwaysByPID) {
+         settings->treeView = false;
+      }
       reaction |= HTOP_RECALCULATE | HTOP_REDRAW_BAR | HTOP_SAVE_SETTINGS;
       result = HANDLED;
    } else if (ch != ERR && this->inc->active) {

Process.c

@@ -505,7 +505,12 @@ long Process_compare(const void* v1, const void* v2) {
       p1 = (const Process*)v2;
    }
 
-   switch (settings->sortKey) {
+   ProcessField key = settings->sortKey;
+   if (settings->treeView && settings->treeViewAlwaysByPID) {
+      key = PID;
+   }
+
+   switch (key) {
    case PERCENT_CPU:
    case PERCENT_NORM_CPU:
       return SPACESHIP_NUMBER(p2->percent_cpu, p1->percent_cpu);

ProcessList.c

@@ -82,7 +82,8 @@ void ProcessList_setPanel(ProcessList* this, Panel* panel) {
 void ProcessList_printHeader(ProcessList* this, RichString* header) {
    RichString_prune(header);
 
-   const ProcessField* fields = this->settings->fields;
+   const Settings* settings = this->settings;
+   const ProcessField* fields = settings->fields;
 
    for (int i = 0; fields[i]; i++) {
       const char* field = Process_fields[fields[i]].title;
@@ -90,10 +91,17 @@ void ProcessList_printHeader(ProcessList* this, RichString* header) {
          field = "- ";
       }
 
-      int color = (this->settings->sortKey == fields[i]) ?
-         CRT_colors[PANEL_SELECTION_FOCUS] : CRT_colors[PANEL_HEADER_FOCUS];
+      int color;
+      if (settings->treeView && settings->treeViewAlwaysByPID) {
+         color = CRT_colors[PANEL_HEADER_FOCUS];
+      } else if (settings->sortKey == fields[i]) {
+         color = CRT_colors[PANEL_SELECTION_FOCUS];
+      } else {
+         color = CRT_colors[PANEL_HEADER_FOCUS];
+      }
+
       RichString_appendWide(header, color, field);
-      if (COMM == fields[i] && this->settings->showMergedCommand) {
+      if (COMM == fields[i] && settings->showMergedCommand) {
          RichString_appendAscii(header, color, "(merged)");
       }
    }

Settings.c

@@ -141,6 +141,8 @@ static bool Settings_read(Settings* this, const char* fileName, int initialCpuCo
          this->direction = atoi(option[1]);
       } else if (String_eq(option[0], "tree_view")) {
          this->treeView = atoi(option[1]);
+      } else if (String_eq(option[0], "tree_view_always_by_pid")) {
+         this->treeViewAlwaysByPID = atoi(option[1]);
       } else if (String_eq(option[0], "hide_kernel_threads")) {
          this->hideKernelThreads = atoi(option[1]);
       } else if (String_eq(option[0], "hide_userland_threads")) {
@@ -287,6 +289,7 @@ bool Settings_write(Settings* this) {
    fprintf(fd, "strip_exe_from_cmdline=%d\n", (int) this->stripExeFromCmdline);
    fprintf(fd, "show_merged_command=%d\n", (int) this->showMergedCommand);
    fprintf(fd, "tree_view=%d\n", (int) this->treeView);
+   fprintf(fd, "tree_view_always_by_pid=%d\n", (int) this->treeViewAlwaysByPID);
    fprintf(fd, "header_margin=%d\n", (int) this->headerMargin);
    fprintf(fd, "detailed_cpu_time=%d\n", (int) this->detailedCPUTime);
    fprintf(fd, "cpu_count_from_one=%d\n", (int) this->countCPUsFromOne);

Settings.h

@@ -44,6 +44,7 @@ typedef struct Settings_ {
    bool degreeFahrenheit;
    #endif
    bool treeView;
+   bool treeViewAlwaysByPID;
    bool showProgramPath;
    bool shadowOtherUsers;
    bool showThreadNames;